كتاب السهو
Read the English translation first, with the original Arabic directly underneath.
It was narrated that Az-Zuhri said:
"I heard Abu Al-Ahwas saying to us in a gathering with Ibn Al-Musayyab when Ibn Al-Musayyab was sitting there, that he had heard Abu Dharr say: The Messenger of Allah (ﷺ) said: "Allah (SWT) continues to look upon His slave while he is praying, so long as he does not turn away. If he turns his face away, He turns away from him."
لاَ يَزَالُ اللَّهُ عَزَّ وَجَلَّ مُقْبِلاً عَلَى الْعَبْدِ فِي صَلاَتِهِ مَا لَمْ يَلْتَفِتْ فَإِذَا صَرَفَ وَجْهَهُ انْصَرَفَ عَنْهُ