‘Abdallah b. ‘Umar told that a man came to the Prophet (ﷺ) and said, “Messenger of God, how often shall I forgive a servant?” He gave no reply, so the man repeated what he had said, but he still kept silence. When he asked a third time he replied, “Forgive him (The verb is in the plural) seventy times daily.” Abu Dawud transmitted it, but Tirmidhi transmitted it from 'Abdallah b. ‘Amr.
Source: sunnah.com
Other translations
Arabic
وَعَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا قَالَ: جَاءَ رَجُلٌ إِلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ: يَا رَسُولَ اللَّهِ كم نَعْفُو عَنِ الْخَادِمِ؟ فَسَكَتَ ثُمَّ أَعَادَ عَلَيْهِ الْكَلَامَ فصمتَ فلمَّا كانتِ الثَّالثةُ قَالَ: «اعفُوا عَنْهُ كُلَّ يَوْمٍ سَبْعِينَ مَرَّةً» . رَوَاهُ أَبُو دَاوُد وَرَوَاهُ التِّرْمِذِيُّ عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو
sunnah.com