مُسْنَدُ أَحْمَدَ
Musnad Ahmad 4067
Musnad of Abdullah bin Mas'ood
It was narrated from Ibn Mas'ood (رضي الله عنه) that A man kissed a woman once, then he came to the Prophet (ﷺ) and asked him about expiation. Then the words "And perform As-Salat (Iqamatas-Salat), at the two ends of the day and in some hours of the night (i.e. the five compulsory Salat (prayers); Verily, the good deeds remove the evil deeds (i.e. small sins)." (Hood 11:114) were revealed. He said: O Messenger of Aliah, is that only for me? He said: “It is for anyone who does that among my ummah.”
Musnad Ahmad 4094lts isnad is saheeh, al-Bukhari (526) and Muslim (2763)]