سنن ابن ماجه

It was narrated from Hudhaifah that he saw Shabath bin Rib’i spitting in front of him. He said: “O Shabath! Do not spit in front of you, for the Messenger of Allah (ﷺ) used to forbid that, and he said: ‘When a man stands up to perform prayer, Allah turns His Face towards him until he turns away or he commits an evil Hadath.’”*
* In Injah Al-Hajah, 'Abdul-Ghani Dehlawi said: "Meaning he does a matter that negates the Khushu'(submissiveness) and attentiveness of his prayer. Or, the meaning of Hadath is invalidating the ablution. The only reason that he described it as 'evil' is because in most cases, its occurrence during prayer is from Shaitan."