—“then bathe.” That is, when a person is in a state of major ritual impurity he must purify his entire body from the crown of his head to the soles of his feet, and this includes rinsing the mouth and inhaling water into the nose; both acts are obligatory in wuḍūʾ and in the full ritual bath (ghusl).
The junub is one upon whom janābah has occurred. Janābah arises either from the discharge of semen accompanied by desire, or from sexual intercourse even if no discharge occurs. Thus, whenever a man has intercourse with his wife he must perform ghusl, whether or not he ejaculates; and whenever ejaculation occurs, ghusl is obligatory whether or not intercourse took place—even if the emission results merely from thinking about it.
He, the Exalted, then says: “If you are ill, or on a journey, or one of you comes from relieving himself, or you have touched women, and you find no water, then perform tayammum with clean earth.” This means that when a person is required to perform wuḍūʾ or ghusl but cannot find water, or is sick and would be harmed by its use, he resorts to tayammum: he strikes the ground with his two palms and wipes his face and hands.
“Then wipe your faces and hands with it. Allah does not intend to burden you.” In what He has prescribed for us He does not wish to impose hardship or difficulty; rather, He is more merciful to us than we are to ourselves, our children, or our mothers. The proof that He is kinder to us than we are to ourselves is His statement, “Do not kill yourselves.” He instructs you not to harm yourself—He is more compassionate toward you than you are toward yourself.
Therefore, through this obligation He does not seek to make things difficult or burdensome for us; instead, “He desires to purify you.” What Allah wants from us through wuḍūʾ and ghusl is to cleanse our outward bodies with water and our inner selves with pure monotheism. For this reason it is recommended, once you have completed wuḍūʾ, to recite the testimony of faith, saying, “I bear witness that there is no god but Allah alone without partner, and I bear witness that…"