Chapter 67: Wedlock, Marriage (Nikaah)
Narrated 'Abdullah: We used to participate in the holy battles led by Allah' s Messenger (ﷺ) and
we had nothing (no wives) with us. So we said, "Shall we get ourselves
castrated?" He forbade us that and then allowed us to marry women with
a temporary contract (2) and recited to us: -- 'O you who believe !
Make not unlawful the good things which Allah has made lawful for you,
but commit no transgression.' ( 5.87)
Sahih al-Bukhari 5075