Before us is the fifth Mishnah in the eighth chapter of tractate Bava Basra. Its topic: what is the law regarding a person who wishes to change the way his heirs inherit from him, meaning to change the basic system established by the Torah. To understand the Mishnah, we must preface with two principles.
Two preliminary principles:
Conditioning against what is written in the Torah - his condition is void: One who attempts to make a condition against what the Torah said, his condition is void and has no meaning. Therefore, the Mishnah will say that a person who says, "I want my daughters to inherit like my sons" - his statement has no halachic meaning.
The law of a shechiv mera (a dying person): A rabbinic enactment that is not directly related to this topic. A person who is on his deathbed and worries that he has not settled his financial affairs, wishes to arrange them now. Although ownership usually only transfers through a formal act of kinyan, the Sages were lenient and established that the oral statement of a shechiv mera acts as a complete kinyan. The reason: the concern that the patient might be overcome with anxiety and distress over not having settled his affairs, and he may die sooner, Heaven forbid. Therefore, the Sages said to him: do not worry, your words are valid - so that he remains calm and peaceful, and with God's help he will relax and recover. (The question of what the law is if he indeed recovered, and whether his words remain valid, is not our concern here and its place is in other Mishnayos.)
The distinction in the Mishnah:
In light of this, the Mishnah distinguishes between two situations: a person who says that after his death the division of the inheritance will change from what the Torah established - his words do not take effect; whereas a person who gives a gift during his lifetime - his gift is valid, since the property is his and he has the right to give from it to whomever he desires and in the manner he desires.
And these are the words of the Mishnah: "Ha'omer ish ploni beni bechor lo yitol pi shenayim" - a person who says in a regular statement (not the statement of a shechiv mera): "I have several sons, and my desire is that they inherit equally and the firstborn should not take a double portion". And similarly, "ish ploni beni lo yirash im echav" - "I have three sons, and my desire is that the older two inherit, whereas the youngest will not take anything". Regarding this, the Mishnah says: "lo amar klum" - his words have no halachic meaning, "shehisnah al mah shekasuv batorah" - he is making a condition regarding the manner of inheritance contrary to what the Torah established, and therefore his statement is void.
A gift during one's lifetime:
On the other hand: "Hamechalek nechasav levanav al piv" - "al piv" means by mouth, and it should be understood in the context of a shechiv mera, who is utilizing the rabbinic leniency that he can transfer ownership with a mere statement. The main point is: he is giving a gift during his lifetime, and therefore it is valid.
"Ribah le'echad umi'et le'echad" - such as one who says: "I have two sons, and my desire is that one takes ninety percent and the other ten percent". "Vehishvah lahen es habechor" - such as one who says: "I have three sons and one of them is a firstborn, and my desire is that they inherit equally, a third to each one". In these cases, if he said that the matter should take effect now while he is still alive - "devarav kayamin", for he gave it as a gift during his lifetime. "Ve'im amar mishum yerushah - lo amar klum": if he said that the matter should take effect as an inheritance, meaning after his death, he has said nothing.
It should be clarified: the concept of "inheritance" in the language of people does not necessarily refer to the halachic mechanism of inheritance. A person might say: "I am giving my sons and daughters equal portions now, so that each one will have an equal portion in my inheritance". This phrasing is not precise, since once he gave it to them as a gift during his lifetime, there is no longer an inheritance to divide - and nevertheless, this is how people are accustomed to speak.
Therefore, the Mishnah establishes that as long as the person noted that the matter acts as a gift, there is no practical difference that he also mentioned the language of inheritance, for his intention is that the matter takes effect now while he is still alive. And regarding this: even though it is within his power to state his will orally from his sickbed, it was customary to put his requests into writing, so that there would be documentation of his will, that everyone would understand the matters uniformly, that doubts would not arise, that there would be witnesses, and that everything would proceed properly.
And this is what the Mishnah said: "Kasav bein batachilah, bein ba'emtza, bein basof mishum matanah" - whether he wrote "I am hereby giving a gift to my children now, so that they will have an equal inheritance", or whether he wrote "My desire is that my children have an equal inheritance, and therefore I am giving them gifts now" - as long as he mentioned the language of a gift in his statement or in the document, "devarav kayamim", since it is clearly evident that his desire is for the matter to take effect while he is still alive as a gift. And if not for this, the matter would not be effective.
Continuation of the Mishnah - Changing the Order of Heirs:
The Mishnah continues with something similar to what was explained above, without adding a real novelty, but serving as an introduction to the words of Rabbi Yochanan ben Berokah: "Ha'omer ish peloni yireshayni bimkom sheyeish bas" - one who says, "I want so-and-so to inherit me even though I have a daughter", and the daughter takes precedence over him in the order of inheritance. And similarly, "biti tireshayni bimkom sheyeish bein" - he has a son, and he says he wants his daughter to inherit. "Lo amar kelum" - this statement has no halachic significance, "shehitnah al mah shekasuv baTorah" - because he has made a condition against what is written in the Torah, as he is stipulating conditions contrary to the Torah's laws.
The Opinion of Rabbi Yochanan ben Berokah:
Rabbi Yochanan ben Berokah partially disagrees with this point, and it is important to understand his words, since the halachah follows his opinion. He maintains that in the case of a person on his deathbed, if he does not change the order of heirs - meaning he does not decree that someone should or should not inherit contrary to the Torah - but merely makes a quantitative change in how much each one receives, his words are valid. For example: he has ten sons, and he says, "I want my favorite son to take half, and the remaining nine will split the rest"; or he has two daughters who are his only heirs, and he says, "I want them to split it sixty-forty." The principle is this: the change is made entirely regarding people who are in line to receive a portion of the inheritance, and everyone takes something; he merely changes the size of their portions, and he is even permitted to change it to the extent that one of them takes everything.
This is the language of the Mishnah: "Rabbi Yochanan ben Berokah omer: im amar al mi shehu ra'uy liyerushah - devarav kayamin" - if he said this regarding someone fit to take from the inheritance, the change is valid, even if it is stated as an inheritance and not as a lifetime gift, provided that he is on his deathbed. "Ve'al mi she'ein ra'uy liyerushah - ein devarav kayamin" - here Rabbi Yochanan ben Berokah concedes that changing things to bequeath to someone who is not in the order of heirs - such as one who says, "I have sons, and I want my nephew to inherit me too" - his words are ineffective. But one who says, "I have sons, and I want one of them to take everything", or dictates an unequal division - his words are valid.
The Firstborn is the Exception:
It is worth noting that even though the halachah follows Rabbi Yochanan ben Berokah, his words do not apply to changing the firstborn's portion - the double portion given to the firstborn remains intact in any case. The reason for this: the Torah itself, in Parashas Ki Seitzei, discusses the firstborn's right in the context of a man who had two wives, one beloved and one hated, and he wishes to bequeath the firstborn's right to the older son of the beloved wife, while the true firstborn is the son born first to the hated wife. The Torah states: you do not have the power to do this and there is no room for preferences, the firstborn is the firstborn. And since the verse states this explicitly, even Rabbi Yochanan ben Berokah concedes that regarding the firstborn one cannot make a change, but in all other matters - one can.
One Who Deeds His Properties to Others:
The final part of the Mishnah: "Hakoseiv et nechasav la'acherim vehiniach et banav - mah she'asah asuy, aval ein ruach chachamim nochah heimenno" - a person who arranges in his lifetime that others will inherit him and not his natural heirs - such as one who has sons and says, "My sons are ruffians, it is better that I give this to my good friend or my nephew" - and he gives it as a gift during his lifetime, "mah she'asah asuy": the action is valid. The strict letter of the law is that by giving the gift during his lifetime the property is indeed transferred, and the sons will inherit nothing. But "ein ruach chachamim nochah heimenno" - meaning the Sages disapprove of this action. The literal meaning of the phrase is: the spirit of the Sages derives no pleasure or peace from this. The main point is that the Sages view this negatively, because even if a person's sons are unsuccessful, perhaps his grandsons will be successful; and the proper order is for a son to inherit from his father, and one should not interfere with this.
"Rabban Shimon ben Gamliel omer: im lo hayu banav nohagin keshurah - zachur latov" - in his opinion, the opposite is true: if a person's sons behave improperly to the extent that leaving the inheritance in their hands would cause an injustice, then transferring it to someone else during his lifetime is a good deed, and Hashem will bless the one who does so. However, the halachah follows the Tanna Kamma, that a person should not disinherit his sons even if they are not the most successful of sons.
In summary: The Mishnah distinguishes between establishing an order of inheritance that differs from Torah law, which is invalid because it constitutes stipulating a condition against what is written in the Torah, and giving a lifetime gift - which includes a deathbed declaration - which is valid, provided it includes the language of a gift. We also learned the opinion of Rabbi Yochanan ben Berokah, which was accepted as halachah, that a person on his deathbed can change the proportions of the division among those eligible for the inheritance but cannot add someone who is ineligible to them, with the exception of the firstborn's portion which cannot be changed; and finally, the opinion of the Sages that the spirit of the Sages takes no pleasure in one who deeds his properties to others and leaves out his sons, and this is how the halachah was decided.