Pirkei Avot - Ethics of the Fathers

~Level 1~
Rabeinu Yonah - "for the sake of Heaven" - an assembly l'Shem Shamayim - for torah and good deeds.

"not for the sake of heaven" - when they assemble to domineer over each other and honor themselves over each other.

~Level 1~
Sfas Emes - even in an assembly for secular needs of this world, let it's intent be l'Shem Shamayim. For "know G-d in all your ways" (Mishlei 3:6).

~Level 2~
Rabeinu Yosef ben Shushan - "any assembly which is for the sake of Heaven will endure.." - whether in a marriage, or when people assemble to make conditions in their dealings (iskehem), or in visiting the sick, or in a funeral procession, or comforting the mourners, or bringing joy to bridegrooms (chatanim) at a wedding - if the aim of their assembling is l'Shem Shamayim (for G-d), it will endure and succeed. But if their assembling is not l'Shem shamayim, it will not succeed and hold.. For "falsehood has no legs". It breaks apart the joined together and all the more so does falsehood not join together the separate. But truth shall stand forever.

~Level 3~
Ruach Chaim - "any assembly which is for the sake of Heaven will in the end endure.." - as known, when a man does a mitzva and fulfills G-d's command, he builds mystical worlds of holiness, as our sages expounded: "do not read [the verse] 'your sons' (banayich), but rather 'your builders' (bonayich)" (Berschot 64a), and as scripture states "I have placed My word in your mouth.. to plant the heavens and lay the foundations of the earth" (Isaiah 51:16).

This is man's reward in Olam Haba. Namely, he is given all the worlds and mystical lights that were added through him. And he delights and enjoys them eternally.

But for sins, it is the opposite. He builds worlds of falsehood and strengthens evil and weakens the powers of good, demolishing and destroying mystical worlds (of good), as scripture states: "those who destroy you and those who lay you waste shall go forth from you.." (Isaiah 49:17). This is the matter of Gehinom.

They exact payment from him after his death, according to the punishment sentenced to him by the Holy One, blessed be He, for the sin.

After he receives the punishment, these forces of evil are destroyed on their own. For their life-force stems only from the sin.

This is what our sages said: "any assembly which is for the sake of Heaven", ie the mystical worlds of holiness he brought and created through his torah study and mitzvah performance - "will in the end endure". For he will delight and enjoy them forever, since they are eternal worlds which endure forever.

But "any assembly which is not for the sake of Heaven.." - ie that were created from sin - "will not endure in the end", as we explained.