It was narrated from 'Uqbah bin 'Amir:
that the Prophet said: "The conditions most deserving to be fulfilled are those by means of which the private parts become permissible for you." (JA)
English reference (JA): Vol. 3, Book 9, Hadith 1954 (JA)
Arabic reference (JA): Book 9, Hadith 2030 (JA)