We are up to Pirkei Avos, chapter 4, mishnah 14 (in some editions these mishnayos are still counted as a continuation of mishnah 12). The author of this teaching is Rabbi Yochanan HaSandlar, whose name reflects his trade as a maker of sandals. He too was among the students of Rabbi Akiva, and among those students who visited their teacher in prison at the end of his life and received rulings of halachah from him.
The text of the mishnah:
"Kol kenesiah shehi l'shem Shamayim sofah l'hiskayem, v'she'einah l'shem Shamayim ein sofah l'hiskayem" - every gathering that is for the sake of Heaven will ultimately endure, and one that is not for the sake of Heaven will not ultimately endure.
Any gathering, assembly, meeting, club or association of many people striving toward a shared goal - if the purpose of that organization, that group, that project or that team is for the sake of Heaven, for the sake of Torah and mitzvos and the like - it will ultimately endure and remain in existence.
Two explanations of the phrase "sofah l'hiskayem":
Endurance over time: the gathering itself will continue and remain in existence over the long term. Avos D'Rabbi Nosson brings an example of this from the revelation at Har Sinai: Israel stood there with one heart and in unity, and the gathering was for the sake of Heaven - and therefore the commitment the Jewish people made at that event stands and continues to this day, and the bond forged there endures.
Endurance of the goals: "sofah" in the sense of its purpose - the goals for which they gathered are what will endure. A government that convenes and acts for the sake of Heaven, the laws it advances will endure, and the initiatives it launches and the things it sets in motion will continue to move forward over time.
And the same applies in reverse: a group that gathers without the proper intentions will not ultimately endure. In the end it will not last, or the goals it seeks to achieve will not be realized.
A precise reading of the word "kenesiah":
Let there be no confusion: in modern Hebrew a "kenesiah" is a Christian house of worship, and that has nothing to do with our subject. But there is a precise point to be made here, since the mishnah could have used the word "kinus," like any ordinary gathering. Why, then, does it say "kenesiah"? The idea is that this word has the letters yud and hey of Hashem's Name added at its end - a gathering that brings Hashem inside it. That is the point: to include Hashem within one's plans.
How does a person know that he really is acting for the sake of Heaven?
A fundamental question arises here: every person believes he is acting for the sake of Heaven, and everyone claims as much. A wonderful line is attributed to the Kotzker Rebbe: "Make sure that your 'for the sake of Heaven' is truly for the sake of Heaven." A person has to examine the banner he is waving and the agenda he is promoting - the one he of course claims is a matter of principle and is the right thing to do - and verify that Hashem really does stand behind it, and not he himself and his ego. And that is no small matter.
A central test: the means do not justify the end
This is an important test for determining whether the interest of Heaven truly lies in one's heart - not the only test, but one of the central ones. True, we are required to make our own effort and do everything in our power. But a person who cuts corners and violates halachah in order to achieve some goal - the ends never justify the means, and someone who lives by that approach is certainly not acting for the sake of Heaven, but is driven by something other than Heaven. For if it were for the sake of Heaven, he would follow Heaven's rules and let matters unfold as they unfold. The Holy One is great, and He can take care of His own affairs Himself.
Tamar as a striking example:
Tamar could have accused Yehudah and said to him, "Don't be angry with me, it is all your fault, you did this to me." But she did not do so, because she was acting for the sake of Heaven. Her entire purpose from the outset, to have children from Yehudah, was for the sake of Heaven, and the proof is that she was not willing to do anything wrong in order to achieve the goal she was striving for.
In summary: We learned from Rabbi Yochanan HaSandlar that a gathering which is for the sake of Heaven will endure in the end - both in its persistence through the generations, like the assembly at Har Sinai, and in the fulfillment of its purposes; we noted the hint contained in the word "kenesiyah," which brings the name of the Holy One into the gathering itself; and we saw the test by which the intention is examined - that the ends do not justify the means, as Tamar demonstrated through her actions.
May this lesson light our way, and with God's help may we merit in all our endeavors to do great things for the sake of Heaven, and to make sure that they are indeed for the sake of Heaven.