Sunan an-Nasa'i, Volume 3, Book 24, Hadith 2922 (DarusSalam) ⓘ
It was narrated from Abdullah bin Ubaid bin Umair that a man said: "O Abu abdur-Rahman, why do I only see you touching these two corners?" He said: "I heard the Messenger of Allah say: 'Touching them erases sins.' And I head him say: 'whoever circumambulates seven times, it is like freeing a slave.'"
حَدَّثَنَا أَبُو عَبْدِ الرَّحْمَنِ، أَحْمَدُ بْنُ شُعَيْبٍ مِنْ لَفْظِهِ قَالَ أَنْبَأَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادٌ، عَنْ عَطَاءٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُبَيْدِ بْنِ عُمَيْرٍ، أَنَّ رَجُلاً، قَالَ يَا أَبَا عَبْدِ الرَّحْمَنِ مَا أَرَاكَ تَسْتَلِمُ إِلاَّ هَذَيْنِ الرُّكْنَيْنِ قَالَ إِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " إِنَّ مَسْحَهُمَا يَحُطَّانِ الْخَطِيئَةَ " . وَسَمِعْتُهُ يَقُولُ " مَنْ طَافَ سَبْعًا فَهُوَ كَعِدْلِ رَقَبَةٍ " .
also referenced under: Hadith 2919 (Reference) & Book 24, Hadith 0 (In-Book)