Siman 493, Se'if 1 (2)

Shulchan Aruch, siman 493, se'if 1: "It is the custom not to marry a woman between Pesach and Shavuos until Lag Ba'omer, because during that period the students of Rabbi Akiva died; but to betroth and to be mekadesh is perfectly fine."
(Shulchan Aruch, se'if 1)

A source for Lag Ba'omer: Here in the Shulchan Aruch we have an explicit mention of Lag Ba'omer, and this is one of the places from which we learn about the standing of that day.

Erusin and kiddushin in the language of Chazal

"To betroth" and "to be mekadesh" are one and the same: In the language of Chazal, erusin and kiddushin are a single act. It is exactly what is done nowadays under the chuppah, when the chosson says "Harei at mekudeshes li."
What we today call "engagement": In today's usage, "erusin" means the shidduchim, what people call a "vort," and that is not the kiddushin the Shulchan Aruch is speaking about. The Shulchan Aruch deliberately uses both expressions, "to betroth and to be mekadesh," so that nobody should come to make this mistake.

Why marriage was forbidden and why kiddushin was permitted

The importance of marriage and its place in simchah

"Lasheves yetzarah": The world was not created for nothing; it was created to be inhabited. One of the most important things in a normal life is that a person marry and fulfill the mitzvah of piryah v'rivyah.
Why specifically marriage was forbidden: Marriage is the mitzvah that carries with it an especially great simchah. Therefore, when the Geonim came to institute a measure of aveilus during the days of Sefiras Ha'omer, the practice they adopted was not to marry, since that is the height of rejoicing.
Kiddushin without marriage: Kiddushin by itself is not such a great simchah; it is only the beginning. That is why it remained permitted.

"To betroth and to be mekadesh is perfectly fine, lest another come first. And it is also permitted to make a se'udas erusin."
(Mishnah Berurah, s.k. 3)

Understanding the reason "lest another come first"

The practical concern: If he waits and does not perform the kiddushin, somebody else may get there ahead of him and be mekadesh that same woman. Therefore we do not hold him back from being mekadesh.
A second match: According to the Gemara, the concern of "lest another come first" was stated regarding a second match.
Even in a first match: Even with a first match one may not rely on the assumption that the matter is already arranged from Heaven, since the Gemara says that tefillah can change things. If somebody else davens, the outcome may turn out differently.
One does not rely on what is not clearly known: Even if a bas kol goes out about a match, a person does not know with certainty that this particular woman is his intended match. Therefore he should not wait and rely on that.

From kiddushin to marriage: from earlier times until our own

The gap in the times of Chazal: In the times of Chazal it was possible to leave as much as a year between the kiddushin and the marriage, and throughout that whole time the arusah is forbidden to him, as we say in the berachah under the chuppah, "Who forbade to us those who are betrothed." She, too, cannot marry anyone else.
The problem with such a gap: Chazal were not happy with the interval between kiddushin and nisuin; it is simply not healthy emotionally. In addition, in Yehudah the practice was that the betrothed couple would eat together in the parents' home, and that led to problems.
The gap was closed after Chazal: In the generations after Chazal the interval was eliminated entirely, and today there is no such thing as kiddushin separated in time from the marriage. Under the chuppah the chosson gives the ring and says "Harei at mekudeshes li b'tabaas zu k'das Moshe v'Yisrael," and that is the kiddushin.
A note on a custom in Gur: A custom that is still practiced today was raised, and it was clarified that one should not get confused: what is involved is shidduchim (a vort) and not kiddushin.
The difference between a vort and kiddushin: Chassidically and socially, breaking a vort is a complicated business, but halachically a vort has no binding force at all, and there is no legal connection between the parties. A married-by-kiddushin woman who is unfaithful to her arus, by contrast, faces a very severe halachah.

What is permitted today: shidduchim and a se'udah

"And nowadays, when kiddushin is performed only at the time of the marriage, it is nonetheless permitted to make shidduchim and to make a se'udah."
(Mishnah Berurah, s.k. 3)

The vort as the substitute for a se'udas erusin: Whatever they permitted in their day as a se'udas erusin, we permit today as shidduchim with a se'udah. Even though there is a certain simchah involved, the families are brought together and a meal is made, this is not the height of rejoicing, and there is already a certain bond formed between the sides, though not as strong a bond as kiddushin.

Dancing

"But to hold dances and circle dances they had the custom to forbid, and all the more so with other, optional dances and circle dances, one certainly must be careful."
(Mishnah Berurah, s.k. 3)

Even dancing connected to a mitzvah: The Mishnah Berurah is speaking about dancing at a se'udas erusin and at shidduchim, where there is an aspect of mitzvah, and even there the custom was to forbid.
A precise look at "one must be careful": A difficulty was raised: for dancing that has a mitzvah aspect he uses the strong language "they had the custom to forbid," while for optional dancing, which is the more serious case, he uses the milder language "one must be careful," when he should have written "it is certainly forbidden." The answer: the wording is indeed misleading, but from the substance of the matter it is clear that optional dancing is the more serious case.
What is not mentioned here: The Mishnah Berurah does not say a single word here about playing music, only about dancing, even though presumably dancing is done with musical instruments.

Rikud and machol: is there a difference?

One possibility: The two terms mean the same thing, just as "to betroth and to be mekadesh" are one thing.
Another possibility: Some distinguish: a machol is public and in a circle, from the expression of moving in a circle, and it involves many people, whereas a rikud can be done even by one person or two.
Sefer Mikra'ei Kodesh: He distinguishes between rikud and machol: a rikud is one or two people, while mecholos are three or more.

Musical instruments and music during the days of Sefirah

The starting point: Since the custom was to forbid dancing, and there is no dancing without music, presumably the custom was to forbid musical instruments as well. However, there is no trace of music in the wording of the Mishnah Berurah, and the whole matter is a custom rather than an explicit halachah, so there is no precise black-and-white standard here.
Which instruments were intended: One has to consider whether the prohibition applies only to the instruments of weddings and dancing, or also to instruments used for another purpose, such as somebody learning to play the piano.
Recorded music: Some wanted to say that the prohibition applies where there is an actual band, whereas a person who turns on a device or a listening service in his home is not included. Others said that there, too, there is in fact a band playing.
Vocal music: Some permit singing with the voice alone, without instruments, and some forbid it.
Music for work and concentration: Rav Shlomo Zalman Auerbach permits it for someone who needs music in order to do his work or to concentrate on his learning, because this is not music of simchah but music of work and of concentration.
A proof from the sailors: The Gemara mentions sailors who would row with oars and sing, because the singing gave them the rhythm, and all the rowers have to be in one rhythm, for otherwise the ship does not move forward. This is not listening to music for its own sake but for the sake of the work.
Kinds of music in our times: There is calming music, music for healing and peace of mind, and music to fall asleep to. It depends what one is listening for, and the definitions in this area are very fluid and not at all clear-cut.

(The shiur is not coming to rule practical halachah here, since where nothing was said explicitly it is hard to lay down firm rules.)

The power of Shabbos to be lenient

Chazzanus on Shabbos: Several points combine here to be lenient: there is an aspect of mitzvah, it is on Shabbos, and it is with the voice rather than with instruments.
Shehecheyanu on Shabbos: There are those who hold that one should not say Shehecheyanu during the days of Sefirah, and even they say that on Shabbos it is permitted, because the restrictions on rejoicing do not take hold on Shabbos as they do on a weekday.
Lag Ba'omer falling on Sunday: According to the Ashkenazic custom one may shave already on Friday, even though Lag Ba'omer itself is on Sunday, because Shabbos combines in and lends the strength to set aside part of the Sefirah restrictions.

One who jumped ahead and married

"And one who jumped ahead and married, we do not punish him."
(Shulchan Aruch, se'if 1)

"This applies specifically to marriage; but if he took a haircut during the days of the Omer, they had the custom to reprimand him and to punish him."
(Mishnah Berurah, s.k. 4)

The case: Someone who did not ask the rabbanim and went ahead and married during the days of Sefirah is not punished.

The difficulty: it should be the reverse

How the customs developed: In the Gemara there is nothing at all on this subject. The custom begins with the Geonim, and the Geonim said only that one does not marry, on account of the students of Rabbi Akiva; not one of them mentioned haircuts. The prohibition of taking a haircut appears only around the twelfth or thirteenth century.
The question: By that reckoning it should have been the case of marriage, the older custom, that we treat more strictly. Yet here it is the reverse: one who violates the haircut restriction is reprimanded and punished, while one who marries is not punished.
The Mishnah Berurah's resolution: With marriage there is a point in his favor, since after all he performed a mitzvah, whereas with a haircut there is no mitzvah whatsoever. A person can restrain himself and take his haircut later; even if he does not look his best, he loses no mitzvah by it.

Someone who has an obligation to take a haircut

A nazir: There is a mitzvah in his shaving.
One released from prison: There is no mitzvah involved, only a dispensation, since in the prisons of those days he had no ability whatsoever to shave or take a haircut.
A king: The Gemara says that a king takes a haircut every day, in the spirit of the verse "Your eyes will behold the king in his beauty."
The Kohen Gadol: He takes a haircut once a week.
A point to consider: Someone who has a representative role before the public, who stands for something he represents, and not merely a personal concern, may well have a special obligation to take a haircut, and it is possible that the penalty would not apply to him. It was noted from the audience that the Mishnah Berurah wrote his words in general terms and did not discuss this distinction at all, and indeed it was offered only as an illustration to help understand the difference, not as a ruling.

In passing · The word "mecholel" and the verse "Choli aretz"

Two roots: "Lecholel" can be explained in two ways: from the word for playing a chalil, a flute, and from the sense of founding and establishing.
The verse in Hallel: "What is with you, O sea, that you flee; the Yarden, that it turns backward; the mountains, that they dance like rams, the hills like young sheep... before the Master, Choli aretz."
One explanation: "Choli" is from the sense of establishing, that the Holy One founded the earth.
A second explanation: "Choli aretz" is a command to the earth that it dance, in the same way as the verse said "the mountains dance like rams," and the verse switched roots for variety of language rather than repeating "tirkedu." This explanation is cited in the name of one of the Rishonim.
In modern usage: "Mecholel" is also the word used for the starter mechanism that cars used to have, and Rav Shapira is called the "mecholel," the originator, of the Daf Yomi.

In passing · Music as a livelihood, and music for a woman who is expecting

A musician who earns his living from it: Both regarding the Three Weeks and regarding the days of Sefirah, the poskim discussed someone whose livelihood is playing music. For Sefiras Ha'omer most poskim are lenient, though there are also those who are strict. A case was cited in which they permitted him to play even within the thirty days because of a commitment he had undertaken.
Music for a woman who is expecting: Nowadays people say there is value in listening to music during pregnancy, much like the need for healthy food. On that basis someone could argue that this is not music of simchah but music for a purpose.
"Fortunate is she who bore him": Of Rabbi Yehoshua it was said, "Fortunate is she who bore him," and it is explained that his mother brought him to the beis midrash while he was still in her womb, so that he should hear the learning. In a similar vein it is said of the chazzan's mother that she brings her son to shul so that he should hear chazzanus.
Foods during the days of Sefirah: There was never a custom to forbid particular foods during the days of Sefirah, and even ice cream is permitted. Such matters are discussed regarding the Nine Days, not regarding Sefirah.

In passing · The berachah on a new car

Hatov Vehametiv instead of Shehecheyanu: Some rely on the position that one should not say Shehecheyanu but rather Hatov Vehametiv, because the car is not the buyer's alone: if he is married, his wife uses the car as well, and wherever there is benefit to another person too, one recites Hatov Vehametiv.