I said, "O Allah's Messenger (ﷺ)! I am a young man and I am afraid that I may commit illegal sexual intercourse and I cannot afford to marry." He kept silent, and then repeated my question once again, but he kept silent. I said the same (for the third time) and he remained silent. Then repeated my question (for the fourth time), and only then the Prophet said, "O Abu Huraira! The pen has dried after writing what you are going to confront. So (it does not matter whether you) get yourself castrated or not."
Sahih al-Bukhari Book 67, Hadith 14
← Previous Hadith 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 Book 67, Hadith 13 Next Hadith → I said, "O Allah's Messenger (ﷺ)! Suppose you landed in a valley where there is a tree of which something has been eaten and then you found trees of which nothing has been eaten, of which tree would you let your camel graze?" He said, "(I will let my camel graze) of the one of which nothing has been eaten before." (The sub-narrator added: `Aisha meant that Allah's Messenger (ﷺ) had not married a virgin besides herself .)

Sahih al-Bukhari Book 67, Hadith 15