Sahih Bukhari Volume 7, Book 67, Hadith 5077

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا جَرِيرٌ، عَنْ إِسْمَاعِيلَ، عَنْ قَيْسٍ، قَالَ قَالَ عَبْدُ اللَّهِ كُنَّا نَغْزُو مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم وَلَيْسَ لَنَا شَىْءٌ فَقُلْنَا أَلاَ نَسْتَخْصِي فَنَهَانَا عَنْ ذَلِكَ ثُمَّ رَخَّصَ لَنَا أَنْ نَنْكِحَ الْمَرْأَةَ بِالثَّوْبِ، ثُمَّ قَرَأَ عَلَيْنَا ‏{‏يَا أَيُّهَا الَّذِينَ آمَنُوا لاَ تُحَرِّمُوا طَيِّبَاتِ مَا أَحَلَّ اللَّهُ لَكُمْ‏}‏‏ الآية

Narrated By 'Abdullah : We used to participate in the holy battles led by Allah's Apostle 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)