ייִדישער מחשבֿה אויף ירמיהו 31:28

That mamzeret posed a difficulty to the Holy Blessed One: the fathers of mamzerim sinned, and their children what did they do?! Is it not already said "Their fathers ate sour grapes, and the teeth of the children shall be blunted?!" (Yirmiyahu 31:28). Are you not a gracious and merciful God, slow to anger and abundant in kindness and truth? Is this called kindness? Is this called truth? Master of the Universe, there is no sin which does not have atonement before You. If I had sinned - I would bring a sacrifice. If I had erred - I would repent. And what shall I do now, that I have not sinned and I have not erred and I am unable to atone for something I have not done?!

The mind of Yirmiyahu was set at rest, for he was concerned about the mamzeirut of his son, Ben Sira, who was born of his daughter when she was impregnated from his semen in a bathtub, and he prophesied: "In those days, they will no longer say 'fathers ate sour grapes and the teeth of their sons are set on edge', for every man will die for his own iniquity, and the one who eats sour grapes, his teeth will be blunted" (Yirmiyahu 31:28-29).