The Table Spread - 5:6
Believers! When you rise for prayer, wash your faces and your hands up to the elbows. Splash your head, and your feet up to the heels, and wash if you have had sexual intercourse. And if you are sick or a traveler, or you have come from the toilet, or you have had sexual intercourse with women and you cannot find water, then turn to a clean piece of earth and rub your face and arms with it. Allah does not wish to cause you any hardship. He only wants to purify you and complete His favor upon you. That you may give thanks.
What is the purpose of prayer?
The Cow/2:45
Seek help by enduring hardship (patience) and prayer. Surely this is burdensome to the people, except for those who are reverent.
The Spider/29:45
Read from the Book which We have revealed to you and observe the prayer. For prayer discourages from abominable and evil things. The remembrance of Allah (through prayer) is most important. Allah knows what you do.
Prophet Hud/11:87
"They said: "Shu´ayb, does your prayer require us to give up what our ancestors used to serve or to turn our trade as we wish? You are indeed mild-tempered and wise."
Ta-Ha/20:14
I, yes, I am Allah; there is no god but Me. Serve Me and observe the prayer in remembrance of Me.
The Most High/87:15
He who remembers the name of his Lord and prays.
The Victory/48:29
Muhammad, the Messenger of Allah, and those who are with him are harsh against the disbelievers and merciful among themselves. You see them bowing down and prostrating themselves, asking Allah for His favor and pleasure. On their faces are the marks of prostration. This is their character in the Torah. And in the Gospel they are like a plant that has sprouted and grown strong and thickened and stood up on its stems, delighting the cultivators. He enrages the disbelievers with them. Allah has promised forgiveness and a great reward to those of them who believe and do righteous deeds.