Question: I remember hearing at a Torah class that the Heavenly Court does not punish one for the sins one commits before the age of twenty. Is this correct?
Answer: The Gemara (Shabbat 89b) tells us that with regards to “laws of Heaven,” the Heavenly Court does not punish before twenty years old. What this means is that there are “laws of man,” i.e. laws for which one is liable for in a human Bet Din (rabbinical court), such as murder, stealing, Shabbat desecration, and the like, which all adults are liable for, meaning a man from the age of thirteen and a woman from the age of twelve.
On the other hand, there are certain laws which are not punishable by a human court but are punishable by the Heavenly Court, such as one who commits his sins secretly where no one can see him, or one who commits sins which are punishable by death in the hands of Heaven (such as one who does not keep the laws of family purity intentionally). All of these individuals cannot be tried by a human Bet Din in this world; however, their punishment will be served by the Heavenly court. When the Gemara says that the Heavenly court does not punish one before the age of twenty, it refers to this category of sins.
Nevertheless, this issue is not quite so simple. The Gemara in Masechet Berachot (31b) states that Shemuel Ha’Navi would have been liable for his sins from the age of two were he to have sinned (for the Gemara explains that Shemuel decided a halachic matter in the presence of Eli the Kohen at which point Eli told him, “You have decided correctly, however, since you have decided a halachic matter in the presence of your rabbi, you are worthy of punishment” if not for his mother, Hannah, intervening on his behalf and changing Eli’s mind).
The same is true with regards to Er and Onan, sons of Yehuda, whom our Sages teach us were put to death by Hashem because of their wicked ways although they were certainly not yet twenty years old. It is thus not absolutely true to say that one is not punished until one is twenty years of age.
Similarly, the saintly Ari z”l instructed his student, Rabbeinu Chaim Vital, to correct his deeds, for he had caused his mother distress when he was but a young infant. It seems from here that, on the contrary, “laws of Heaven” are more stringent than the “laws of man,” for he was judged for his actions even before the age of thirteen.
Maran Harav Ovadia Yosef Shlit”a explains this matter (in his Ma’or Yisrael, Volume 1, page 46 on Berachot 31b) and writes that with regards to “laws of man,” it always depends on one’s physical age, for if one has already reached the age of Mitzvot, one is considered an adult (for most matters besides for several others which one needs to be older to be included in) and if one has not yet reached the age of Mitzvot, he is considered a minor and is not liable for his actions.
However, with regards to the “laws of Heaven,” it depends on one’s individual level, for if one is sharp and intelligent, Heaven will seek judgment even for those actions that one performs in his youth. On the other hand, if one is not so intelligent, one will only be punished in Heaven when he reaches twenty years of age. When our Sages said that “Heaven does not punish one until the age of twenty,” they were referring to the general populace among whom are individuals who are not intelligent enough to understand the gravity of their actions. He proceeds to support his explanation with various sources.
Summary: With regards to sins punishable only by Heaven, there is no set age at which one becomes liable for one’s actions. It all depends on the intelligence and maturity of the individual, for if one is a responsible person, one may be held accountable even from a young age. However, if one is not so responsible, one will receive Heavenly mercy and be held accountable only from the age of twenty.