O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous

Narrated by `Abdullah We were with the Prophet while we were young and had no wealth whatever. So Allah`s Apostle said, "O young people! Whoever among you can marry, should marry, because it helps him lower his gaze and guard his modesty (i.e. his private parts from committing illegal sexual intercourse etc.), and whoever is not able to marry, should fast, as fasting diminishes his sexual power."