According to various religions it is possible to resolve various ailments or absolve sins through ritual washing, called ablution.

The Christian practices of baptism and foot-washing are instances of ablution.

Table of contents
1 Ablution in the Bible
2 Ablution in Islam
3 Ablution in Shakespeare

Ablution in the Bible

From Easton's Bible Dictionary (1897)

Ablution, or washing, was practised, (1.) When a person was initiated into a higher state: e.g., when Aaron and his sons were set apart to the priest's office, they were washed with water previous to their investiture with the priestly robes (Lev. 8:6).

(2.) Before the priests approached the altar of God, they were required, on pain of death, to wash their hands and their feet to cleanse them from the soil of common life (Ex. 30:17-21). To this practice the Psalmist alludes, Ps. 26:6.

(3.) There were washings prescribed for the purpose of cleansing from positive defilement contracted by particular acts. Of such washings eleven different species are prescribed in the Levitical law (Lev. 12-15).

(4.) A fourth class of ablutions is mentioned, by which a person purified or absolved himself from the guilt of some particular act. For example, the elders of the nearest village where some murder was committed were required, when the murderer was unknown, to wash their hands over the expiatory heifer which was beheaded, and in doing so to say, "Our hands have not shed this blood, neither have our eyes seen it" (Deut. 21:1-9). So also Pilate declared himself innocent of the blood of Jesus by washing his hands (Matt. 27:24). This act of Pilate may not, however, have been borrowed from the custom of the Jews. The same practice was common among the Greeks and Romans.

The Pharisees carried the practice of ablution to great excess, thereby claiming extraordinary purity (Matt. 23:25). Mark (7:1-5) refers to the ceremonial ablutions. The Pharisees washed their hands "oft," more correctly, "with the fist" (R.V., "diligently"), or as an old father, Theophylact, explains it, "up to the elbow." (Compare also Gospel of Mark 7:4; Lev. 6:28; 11: 32-36; 15:22) (See Washing.)

Ablution in Islam

Wudhu or ablution is observed by Muslims preceding each prayer, if one is in a state of impurity. Physical cleanliness before Allah (God) is deemed a necessity and purification is intended for not only ones soul, but body as well. One must wash the face, feet, hands, ears, arms and other bodily regions prior to prayer recitation and prostrations. If footwear remains clean but the ablution becomes invalid, one is allowed to just gently pass wet fingers on the upper part of the foot garment, but the other prerequisites still must be carried out. Ablution remains valid for up to twenty-four hours (or in case of a journey, three days) and is nullified if blood, pus or vomit is drawn, if one urinates, passes wind or stool, or falls into deep sleep. If clean or sufficient quantities of water are unavailable, worshippers are allowed to use clean sand or earth on the face and hands. Cleansing oneself is also committed before one touches the Holy Qur'an, the authoritive holy text for Muslims. A full body ablution is carried out after sexual intercourse or if one intends to visit the local places of worship.

Ablution in Shakespeare

"Out, out damned spot", cries Lady Macbeth, unable to cleanse her guilt by washing her hands.