Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1087
This hadith is narrated on the authority of Alqama and Aswad by another chain of transmitters and in the hadith transmitted by Ibn Mus-hir and Jabir the words are:" I perceive as if I am seeing the gap between the fingers of the Messenger of Allah (may peace be upon him) as he was bowing."