An-Nisa - آية 43

O you who have believed, do not approach prayer while you are intoxicated until you know what you are saying1 or in a state of janābah,2 except those passing through [a place of prayer], until you have washed [your whole body]. And if you are ill or on a journey or one of you comes from the place of relieving himself or you have contacted women [i.e., had sexual intercourse] and find no water, then seek clean earth and wipe over your faces and your hands [with it]. Indeed, Allāh is ever Pardoning3 and Forgiving.