Musnad Abu Ya'la al-Mawsili 154:58

Abu Khaythama narrated to us, Hushaym narrated to us, ‘Ata’ ibn al-Sa’ib narrated to us, from ‘Abdullah ibn ‘Ubayd ibn ‘Umayr, that he heard his father say: I said to Ibn ‘Umar, "Why do I see you touching only these two corners: the Black Stone and the Yemeni Corner?" Ibn ‘Umar said: "If I do so, it is because I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: 'Touching them removes sins.' And I heard him say: 'Whoever performs a circumambulation (tawaf) counting it, and prays two rak'ahs, it is for him like the freeing of a slave.' And I heard him say: 'A man does not lift a foot nor place it down except that ten good deeds are written for him, ten evil deeds are removed from him, and he is raised ten degrees.'"