4:43
O you who believe[d]! (Do) not go near the prayer while you (are) intoxicated until you know what you are saying and not (when you are) impure except (when) passing (through) a way until you have bathed. And if you are ill or on a journey or came one of you from the toilet, or you have touched the women and not you find water, then do tayammum (with) earth clean and wipe (with it) your faces and your hands. Indeed, Allah is Oft-Pardoning, Oft-Forgiving.

5:6
O you who believe! When you stand up for the prayer, then wash your faces and your hands till the elbows and wipe your heads and your feet till the ankles. But if you are (in) a state of ceremonial imp then purify yourselves. But if you are ill or on a journey or has come anyone of you from the toilet or has (had) contact (with) the women and not you find water, then do (with) earth clean, then wipe your faces and your hands with it. Does Not intend Allah to make for you any difficulty but He intends to purify you and to complete His Favor upon you so that you may (be) grateful.