4:43

O you who have believed, do not approach prayer while you are intoxicated until you know what you are saying or in a state of janabah, 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 and find no water, then seek clean earth and wipe over your faces and your hands [with it]. Indeed, Allah is ever Pardoning and Forgiving.
Meaning:-
Janabah: Junub is an Islamic term meaning ritually impure due to sexual intercourse or seminal discharge. A person in such a state needs to take a bath in order to become ritually pure and be able to perform his prayers. A person while in a state of janaba cannot offer his/her daily salat (prayer) or enter a mosque.