Mishkat al-Masabih 2580
‘Ubaid b. ‘Umair said:
Ibn ‘Umar used to press towards the two corners in a manner I have not seen any of the companions of God’s messenger press. He said, “If I do so, it is because I heard God’s messenger say that stroking them is an atonement for sins; and I heard him say that if anyone goes round this House for a week and counts his circuits, it will be like setting free a slave; I heard him say that no one will place one foot on the ground and raise the other without God removing a sin from him on account of it and recording a blessing for him on account of it.” 

Tirmidhi transmitted it.
وَعَن عُبيدِ بنِ عُمَيرٍ: أَنَّ ابْنَ عُمَرَ كَانَ يُزَاحِمُ عَلَى الرُّكْنَيْنِ زِحَامًا مَا رَأَيْتُ أَحَدًا مِنْ أَصْحَابِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُزَاحِمُ عَلَيْهِ قَالَ: إِنْ أَفْعَلْ فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «إِنَّ مَسْحَهُمَا كَفَّارَةٌ لِلْخَطَايَا» وَسَمِعْتُهُ يَقُولُ: «مَنْ طَافَ بِهَذَا الْبَيْتِ أُسْبُوعًا فَأَحْصَاهُ كَانَ كَعِتْقِ رَقَبَةٍ» . وَسَمِعْتُهُ يَقُولُ: «لَا يَضَعُ قَدَمًا وَلَا يَرْفَعُ أُخْرَى إِلا حطَّ اللَّهُ عنهُ بهَا خَطِيئَة وكتبَ لهُ بهَا حَسَنَة» . رَوَاهُ التِّرْمِذِيّ