Hadith 8:517
Abu Bakr narrated to us, he said: Hafs narrated to us, from 'Asim, he said: I saw Anas bin Malik circumambulating the House. When he became parallel with the Stone (the Black Stone), he looked at it and turned toward it, then he said "Allahu Akbar" (God is the Greatest) toward it.
حدثنا أبو بكر قال ثنا حفص عن عاصم قال رأيت أنس بن مالك يطوف بالبيت حتى إذا حاذى بالحجر نظر إليه والتفت إليه فكبر نحوه