Good Manners and Form (Al-Adab)

Bukhari :: Book 8 :: Volume 73 :: Hadith 128

Narrated Abu Huraira:

Allah's Apostle said: "Whoever amongst you swears, (saying by error) in his oath 'By Al-Lat and Al-Uzza', then he should say, 'None has the right to be worshipped but Allah.' And whoever says to his companions, 'Come let me gamble' with you, then he must give something in charity (as an expiation for such a sin)." (See Hadith No. 645)