The Prophet ﷺ would spread his fingers apart when he bowed, and bring them together when he prostrated.
أن النبي ﷺ كان إذا ركع فرج أصابعه، وإذا سجد ضم أصابعه.
Ibn Khuzayma (594), Ibn Hibban (1920), Hakim (1/227), and Bayhaqi (2/112) all narrated it through the hadith of Harith bin Abdullah bin Ismail bin Uqba bin Khazin, who said, Hushaym narrated to us, from Asim bin Kulayb, "from Alqama bin Waail bin Hujr, from his father," and then he related the hadith. Its isnad is hasan on account of Ibn Khazin, for he is hasan al-hadith. Ibn Hibban mentioned him in Thiqat and said, "His hadith is straightforward." Dhahabi said in Mizan, "Truthful."As for Hakim's statement, "sahih according to the criteria of Muslim," this is a mistake on his part, for this Ibn Khazin is not among the men found in Tahdhib at all.However, Hakim (1/224) also narrated it by another route, from Amr bin Awn, who said, Hushaym narrated to us with his isnad, and he said, "according to the criteria of Muslim," and it is as he said.