Sunan Ibn Majah, Book 5, Hadith 1457 (In-Book) ⓘ
It was narrated from ‘Abdur-Rahman bin Ka’b bin Malik that his father said that when Allah accepted his repentance, he fell down prostrate.
حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، عَنْ مَعْمَرٍ، عَنِ الزُّهْرِيِّ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ كَعْبِ بْنِ مَالِكٍ، عَنْ أَبِيهِ، قَالَ لَمَّا تَابَ اللَّهُ عَلَيْهِ خَرَّ سَاجِدًا .
also referenced under: Hadith 1393 (Reference) & Volume 2, Book 5, Hadith 1393 (DarusSalam)