Sunan Abu Dawud
4533
Sahih+3

Narrated Abu Hurairah:That Sa'd b. 'Ubadah said to the Messenger of Allah (ﷺ) : What do you think if I find with my wife a man ; should I give him some time until I bring four witnesses ?" He said: "Yes

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid