ENOfficial
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.
Source: sunnah.com
Other translations
Arabic
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 .
sunnah.com