Musnad Ahmad

It is narrated from Hazrat Ya'la (may Allah be pleased with him) that I was with Hazrat Umar (may Allah be pleased with him), he performed istilam of the Black Stone, and I was near the House of Allah. When I reached the western corner with the Black Stone and raised my hand to perform istilam, Hazrat Umar (may Allah be pleased with him) said, "What are you doing?" I said, "Do you not perform istilam of both these corners?" He said, "Did you not perform tawaf with the Prophet (peace and blessings of Allah be upon him)?" I said, "Why not?" He said, "Did you see the Prophet (peace and blessings of Allah be upon him) performing istilam of these two western corners?" I said, "No." He said, "Then is there not a good example for you in the way of the Prophet (peace and blessings of Allah be upon him)?" I said, "Why not?" He said, "Then stop it."