Kitto's Popular Cyclopedia of Biblial Literature
Ablution, the ceremonial washing, whereby, as a symbol of purification from uncleanness, a person was considered—
to be cleansed from the taint of an inferior and less pure condition, and initiated into a higher and purer state (Leviticus 8:6);
to be cleansed from the soil of common life, and fitted for special acts of religious service (Exodus 30:17-21);
to be cleansed from defilements contracted by particular acts or circumstances, and restored to the privileges of ordinary life (Leviticus 12-15);
as absolving or purifying himself, or declaring himself absolved and purified, from the guilt of a particular act (Deuteronomy 21:1-9).
We do not meet with any such ablutions in patriarchal times: but under the Mosaic dispensation they all occur.
After the rise of the sect of the Pharisees, the practice of ablution was carried to such excess, from the affectation of excessive purity, that it is repeatedly brought under our notice in the New Testament through the severe animadversions of our Savior on the consummate hypocrisy involved in this fastidious attention to the external types of moral purity, while the heart was left unclean. All the practices there exposed come under the head of purification from uncleanness—the acts involving which were made so numerous that persons of the stricter sect could scarcely move without contracting some involuntary pollution. For this reason they never entered their houses without ablution, from the strong probability that they had unknowingly contracted some defilement in the streets; and they were especially careful never to eat without washing the hands (Mark 7:1-5), because they were peculiarly liable to be defiled; and as unclean hands were held to communicate uncleanness to all food (excepting fruit) which they touched, it was deemed that there was no security against eating unclean food but by always washing the hands ceremonially before touching any meat. The Israelites, who, like other Orientals, fed with their fingers, washed their hands before meals, for the sake of cleanliness [WASHING]. But these customary washings were distinct from the ceremonial ablutions. It was the latter which the Pharisees judged to be so necessary. When therefore some of that sect remarked that our Lord's disciples ate 'with unwashen hands' (Mark 7:2), it is not to be understood literally that they did not at all wash their hands, but that they did not plunge them ceremonially according to their own practice. In at least an equal degree the Pharisees multiplied the ceremonial pollutions which required the ablution of inanimate objects—'cups and pots, brazen vessels and tables;' the rules given in the law (Leviticus 6:28; Leviticus 11:32-36; Leviticus 15:23) being extended to these multiplied contaminations. Articles of earthenware which were of little value were to be broken; and those of metal and wood were to be scoured and rinsed with water.
Kitto, John, ed. Entry for 'Ablution'. "Kitto's Popular Cyclopedia of Biblial Literature". https://www.studylight.org/encyclopedias/eng/kbe/a/ablution.html.