All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
At-Tabaraani in Al-Mu’jam Al-Kabeer and Al-Bayhaqi in Shu’ab Al-Eemaan reported from Abu Umaamah that the Prophet said: “The angel on the left-hand side (who records sins) holds up his pen (refrains from writing down) for six hours after a Muslim commits a sin. If the person regrets it and asks Allah for forgiveness, he casts it aside (does not write it down); otherwise, it is written down as one (bad deed).”
Shaykh Al-Albaani classified it as Hasan in Saheeh Al-Jaami’ As-Sagheer, and he quoted it in As-Silsilah As-Saheehah.
Allah knows best.