Imām Bukhārī narrates: 'Abdul-'Azīz ibn 'Abdullāh narrated to us, he said: Ibrāhīm ibn Sa'd narrated to us, from his father, from Hafs ibn 'Āsim, from 'Abdullāh ibn Mālik ibn Buhainah, he narrated that the Prophet ﷺ passed by a person. Imām Bukhārī said: And 'Abdur-Rahmān narrated to me, he said: Bahz ibn Asad narrated to me, he said: Shu'bah narrated to me, he said: Sa'd ibn Ibrāhīm informed me, he said: I heard Hafs ibn 'Āsim, he said: I heard a person of the tribe of Azd, who was called Mālik ibn Buhainah, that:

the Messenger of Allāh ﷺ saw a person praying two rak'ahs, and at that time the iqāmah for the prayer had already been given. When the Messenger of Allāh ﷺ finished the prayer, the people surrounded him. So the Messenger of Allāh ﷺ said to him: Is the Fajr prayer four rak'ahs? Is the Fajr prayer four rak'ahs?

Ghundar and Mu'ādh have corroborated Bahz ibn Asad in this hadith, from Shu'bah, from Mālik. And Ibn Ishāq said: from Sa'd, from Hafs, from 'Abdullāh ibn Buhainah. And Hammād said: Sa'd informed us, from Hafs, from Mālik.