Musnad Ahmad 25:1673

Rawh narrated to us, Sa’id and ‘Abd al-Wahhab narrated to us, from Sa’id, from Qatadah, from Abu al-Tufayl, who said: Mu’awiyah would not come to a corner of the House (the Kaaba) without touching it. Ibn ‘Abbas said: "The Prophet of Allah, peace and blessings of Allah be upon him, only used to touch these two corners." Mu’awiyah said: "There is nothing of its corners that is abandoned." ‘Abd al-Wahhab said: "The two corners are the Yemeni (corner) and the Black Stone (corner)."