سنن النسائي

It was narrated from Sulaiman bin Buraidah that his father said: "The Messenger of Allah (ﷺ) said: 'The sanctity of the wives of the Mujahidin to those who stay behind is like the sanctity of their mothers. There is no man who takes on the responsibility of looking after the wife of one of the Mujahidin and betrays him with her but he (the betrayer) will be made to stand before him on the Day of Resurrection and he will take whatever he wants of his (good) deeds. So what do you think?'"