Term originally denoting a coarsely woven fabric, usually made of goat's hair. It afterward came to mean also a garment made from such cloth, which was chiefly worn as a token of mourning by the Israelites. It was furthermore a sign of submission (1 Kings 20:30 et seq.), and was occasionally worn by the Prophets.
As the Old Testament gives no exact description of the garment, its shape must be a matter of conjecture. According to Kamphausen, the saḳ was like a corn-bag with an opening for the head, and another for each arm, an opening being made in the garment from top to bottom. Grüneisen ("Ahnenkultus," p. 80) thinks the saḳ resembled the hairy mantle used by the Bedouins. Schwally (in Stade's "Zeitschrift," 11:174) concludes that it originally was simply the loin-cloth, which is an entirely different conception from that of Kamphausen or of Grüneisen. Schwally bases his opinion on the fact that the word "ḥagar" is used in describing the mode of putting on the garment (see Joshua 1:8; Isaiah 3:24, 15:8, 22:12; Jeremiah 6:26, 49:3). One fastens the saḳ around the hips ("sim be-motnayim," Genesis 37:34; "he'elah 'al motnayim," Amos 8:10), while, in describing the doffing of the saḳ, the words "pitteaḥ me-'al motnayim" are used (Isaiah 20:2). According to 1 Kings 21:37 and 2 Kings 6:30, it was worn next the skin.
Schwally assumes that in prehistoric times the loin-cloth was the usual and sole garment worn by the Israelites. In historic times it came to be worn for religious purposes only, on extraordinary occasions, or at mourning ceremonies. It is natural that, under certain circumstances, the Prophets also should have worn the saḳ, as in the case of Isaiah, who wore nothing else, and was commanded by Yhwh to don it (Isaiah 20:2). Old traditions about to die out easily assume a holy character. Thus Schwally points to the circumstance that the Moslem pilgrim, as soon as he puts his foot on Ḥaram,the holy soil, takes off all the clothes he is wearing, and dons the iḥram.
The views mentioned above of the original shape of the saḳ. do not, of course, exclude the possibility that, in accordance with more refined ideas, it was afterward made larger, and in later passages (e.g., Esther 4:1,2; Jonah 3:5) the verb "labash" is used in describing the mode of putting it on.