The Statement of Allah"...If you are in a state of Janaba (i .e., after a sexual discharge), purify yourselves (bathe your whole body). But if you are ill or on a journey or any of you comes from answering the call of nature, or you have had been in contact with women (i .e. sexual intercourse) and you find no water then perform Tayammum with clean earth and rub therewith your faces and hands. Allah does not want to place you in difficulty, but He wants to purify you and to complete His Favour to you, that you may be thankful.” (V.5 :6)
And also the Statement of Allah “O you who believe! Approach not As-Salat (the prayer) when you are in a drunken state until you know (the meaning) of what you utter, nor when you are in a state of Jandba (i.e., in a state of sexual impurity and not have yet taken a bath) except when travelling on the road (without enough water, or just passing through a mosque), till you wash your whole body. And if you are ill or on a journey or one of you comes after answering the call of nature, or you have been in contact with women (by sexual relations) and you find no water then perform Tayammum with clean earth and rub therewith your faces and hands (Tayammum). Truly Allah is Ever Oft- Pardoning, Oft—Forgiving.” (V.4 :43)
The Perfomance Of Ablution Before Taking Bath
1.Narrated 'Aisha RA, Whenever the Prophet took a bath after janaba, he started by washing his hands and then performed ablution like that for Salat (prayer). After that he would put his fingers in water and move the roots of his hair with them, and then pour three handfuls of water over his head and then pour water all over his body. (Bukhari,The book of Ghusl,Hadith no 248)
2.Narrated Maimuna RA ,( The wife of the Prophet) Allah’s Messenger performed ablution like that for Salat (prayer) but did not wash his feet.... He washed off the discharge from his private parts and then poured water over (his body). He withdrew his feet from that place (the place where he took the bath) and then washed them. And that was his way of taking the bath of Janaba.(Bukhari,The book of Ghusl,Hadith no 249)