Saa’sa’a, the uncle of [the famous poet] al-Farazdaq, came to the Prophet Muhammad (PBUH). When he heard [the Prophet recite] the verses “So whoever does an atom’s weight of good will see it; And whoever does an atom’s weight of evil will see it”, he [Saa’sa’a] said,” [These verses are] enough for me! I would be fine if I did not hear anything other than these [verses].”
References: Majma’ul Bayan Vol 10, Pg 800 – Musnad Hanbal, Vol 34 Hadith No: 20595