Chapter on the Manner of Prayer, Explanation of the Fifty-One Rak‘ahs; The Order, Recitation, Tasbih in Bowing and Prostration, Qunut, and What is Obligatory and Recommended Therein

And from him, from Ibn Abi Umayr, from ‘Umar ibn Udhaynah, from Zurarah, from one of the two (Imams) (peace be upon them), who said: I asked (Imam عليه السلام) about a man prostrates while wearing a cap or a turban. Imam عليه السلام said: “If his forehead touches the ground in the area between his eyebrows and the hairline, then it suffices for him.”