From Sahih Muslim (Hadith 1192):
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 (ﷺ) as he was bowing
Reference: Muslim 1192