Skins of animals were used as bottles both for water and for wine. They formed many useful articles for clothing. Various kinds formed the protection for the tabernacle in the wilderness. Ezekiel tells of shoes being made from skins (Ezek.16.10 kjv; niv “leather”).
The word is also used figuratively in several places (Job.2.4; Job.19.20). The two Greek words are used only three times in the NT (Matt.3.4; Mark.1.6; Heb.11.37) and in each case speak of articles of clothing.
If new wine is put into old wineskins “the skins burst, and the wine is spilled, and the skins are destroyed; but new wine is put into fresh wineskins, and so both are preserved” (Matt 9:17).
As the skin bottle grew old it lost its elasticity, becoming hard and brittle. New wine was still fermenting and the expansion caused by the resulting gases was easily accommodated by a new stretchable bottle. Obviously, the new wine would burst an old bottle. The point of the Lord’s parable is that an elastic mind able to receive a new thought, is like a new wine skin.
There are some references to human diseases of the skin. That Job in his affliction suffered from smallpox is a good possibility. He was afflicted with sores from head to toe, to the extent that his friends could not recognize him (Job 2). The condition was very itchy, for he scraped himself with a piece of broken pottery. He commented that “my skin hardens, then breaks out afresh” (Job 7:5). All this fits smallpox, although there are other possibilities.
Leprosy was a dreaded skin disease throughout the OT and NT. In the time of Moses, who had advanced ideas on preventive medicine, it was the duty of the priest to decide whether a man had active leprosy, which made it necessary for him to live apart from his people. The priest also had to decide if the disease was burned out. The criteria used in his examination of the patients are laid down in Leviticus 13. Christ cleansed ten lepers. This healing involved a restoring of the damaged parts of the body (Luke 17:11-19).
There are well-known proverbs concerning skin that come from the Bible. Job declared “I have escaped by the skin of my teeth” (Job 19:20). Jeremiah asked “Can the Ethiopian change his skin or the leopard his spots?” (Jer 13:23). See Tanner.
International Standard Bible Encyclopedia (1915)
(`or, geledh, "human skin" (Job 16:15), basar, "flesh," in the sense of "nakedness" (Ps 102:5 the King James Version); derma):
The word `or designates the skin of both men and animals, the latter both raw and in tanned condition: "Yahweh God made for Adam and for his wife coats of skins (`or), and clothed them" (Ge 3:21); "She put the skins (`or) of the kids of the goats upon his hands, and upon the smooth of his neck" (Ge 27:16); "Can the Ethiopian change his skin, or the leopard his spots?" (Jer 13:23). The Hebrew geledh is found in the sense of human skin: "I have sewed sackcloth upon my skin, and have laid my horn in the dust" (Job 16:15).
`To escape by the skin of the teeth’ is equivalent to a narrow escape (Job 19:20). Satan says in his calumny of Job: "Skin for skin, yea, all that a man hath will he give for his life" (Job 2:4). The idea here is, that a man will endure or do the worst, even as it were the flaying of his body, to save his life. The Revised Version (British and American) has replaced "skin" as the translation of Hebrew basar by "flesh": "My bones cleave to my flesh" (Ps 102:5). "The bars of his skin" is a poetical expression for "the members of his body" in Job 18:13 margin, where the text interprets rather than translates the original.
The Revised Version, rejecting the translation "badgers’ skins," substitutes "sealskins" and adds "porpoise skins" in the margin. There is little doubt that the rendering of the King James Version is indeed incorrect. The Hebrew name of the animal (tachash) is the same as the Arabic tuchas, which means the dolphin and the "sea-cow" or halicore of the Red Sea, of which genus there are two species even now extant (H. tabernaculi Russ, and H. Helprichii Ehr.). It is probable that the Jews included various marine animals, seals, porpoises, dolphins and halicores, under the same expression.
In Eze 16:10 we find these skins mentioned as material for elegant shoes, and the Arabs of the Red Sea littoral use the same material in the manufacture of sandals. A quaint use was made of skins in the making of skin bottles, the qurbeh or qirbeh of modern Arabia. We find a great variety of Hebrew expressions, which possibly designated special varieties, all of which were rendered askos, in Septuagint and the New Testament (chemeth, no’dh, no’dhah, nebhel, nebhel, baqbuq, ’obh). the Revised Version (British and American) has rendered the Greek askos in the New Testament by "wineskin" (Mt 9:17; Mr 2:22; Lu 5:37) with the marginal addition "that is, skins used as bottles." These skin bottles were made of the skins of goats, sheep, oxen or buffaloes; the former had more or less the shape of the animals, the holes of the extremities being closed by tying or sewing, and the neck of the skin being closed by a tap or a plug, while the larger ones were sewn together in various shapes. As a rule only the inside of the skin was tanned, the skin turned inside out, and the fluid or semi-fluid filled in, e.g. water, milk, butter, cheese. The hairy inside was not considered as in any way injurious to the contents. Only in the case of wine-and oil-skins was it thought advantageous to tan the skins inside and out.