Majma al-Zawaid — Hadith 16381

Yazid bin Umayrah said: Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) told me this in his final counsel: Some men from among the Companions of the Prophet (peace and blessings be upon him) said one day: "Our children are better than us, because they were born in Islam and have never committed shirk, while we used to commit shirk." When this reached the Prophet (peace and blessings be upon him), he said: "We are better than our children, our children are better than their children, and our children's children are better than their children's children."
Imam al-Tabarani recorded it within a long hadith. Its chain contains a narrator, Mu'awiyah bin Imran al-Jarmi, whom I do not know; the remaining narrators of this report are thiqat (trustworthy).