Musnad Ahmad 2:300

Waki’ narrated to us, Sufyan narrated to us, from Ibrahim ibn ‘Abd al-A’la, from Suwayd ibn Ghafalah: That ‘Umar kissed it and embraced it, then said: "I saw Abu al-Qasim (may Allah bless him and grant him peace) being affectionate toward you"—meaning the Black Stone.