Sunan an Nasai
3474
Sahih+2

It was narrated that Sa'eed bin Jubair said:"Al-Mus'ab did not separate the two who engaged in Li'an." Sa'eed said: "I mentioned that to Ibn 'Umar and he said: 'The Messenger of Allah separated the couple from Banu 'Ajlan

SahihAbu Ghuddah
SahihAl-Albani