This word is used a number of times in the Bible both literally and figuratively. In both cases the shoulder is usually shown as the part of the body bearing a burden. This is natural since it is the only part of the body with an appreciable horizontal portion.
The ancients carried heavy objects such as water jars on the shoulder (Gen 21:14). The shepherd who found his lost sheep (Luke 15:5) is depicted as carrying it back upon his shoulders. There is an echo here of Yahweh’s dealings with His children in Deut 33:12. Both these portions illustrate man’s helplessness and total dependence on God in dealing with personal sin.
Figuratively, shoulder usually indicates submission, whether it be to an unwelcome burden or an accepted responsibility. Matthew, in reference to the unnecessary laws imposed on man by the Pharisees instead of true commitment to God, says “they bind heavy burdens, hard to bear, and lay them on men’s shoulders” (Matt 23:4). Isaiah relates the Lord’s promise to break the Assyrians’ yoke upon His people and remove the burden from their shoulders (Isa 14:25). The early priests were instructed to wear an ephod with a stone on the shoulder pieces in which were engraved the names of the tribes (Exod 28:1-12). This meant that the priests bore the responsibility of the people’s spiritual life. Finally, Isaiah, speaking prophetically of Christ, referred to the responsibility of judgment when he said “the government will be upon his shoulder” (Isa 9:6).
International Standard Bible Encyclopedia (1915)
The shoulders also bear responsibility and power. Thus it is said of King Messiah, that "the government shall be upon his shoulder" (Isa 9:6) and "the key of the house of David will I lay upon his shoulder; and he shall open, and none shall shut; and he shall shut, and none shall open" (Isa 22:22). Job declares that he will refute all accusations of unlawful conduct made against him, in the words: "Oh .... that I had the indictment which mine adversary hath written! Surely I would carry it upon my shoulder" (Job 31:35 f).
Stubborn opposition and unwillingness is expressed by "withdrew the shoulder" (Ne 9:29), or "pulled away the shoulder" (Zec 7:11), where the marginal rendering is "they gave (or "turned") a stubborn shoulder." Contrast "bow the shoulder," i.e. "submit" (Baruch 2:21). Compare "stiffnecked"; see Neck. Somewhat difficult for the understanding of Occidentals is the poetical passage in the blessing of Moses: "Of Benjamin he said, The beloved of Yahweh shall dwell in safety by him; he covereth him all the day long, and he dwelleth between his shoulders" (De 33:12). The "shoulders" refer here to the mountain saddles and proclivities of the territory of Benjamin between which Jerusalem, the beloved of Yahweh, which belonged to Judah, lay nestling close upon the confines of the neighboring tribe, or even built in part on ground belonging to Benjamin.
Much less frequently than the above-mentioned words. we find zeroa`, zero`ah, which is used of the "boiled shoulder of the ram" which was a wave offering at the consecration of a Nazirite (Nu 6:19) and of one of the priestly portions of the sacrifice (De 18:3). In Sirach 7:31 this portion is called brachion, properly "arm," but both the King James Version and the Revised Version (British and American) translate "shoulder." Regarding the wave and heave offerings see SACRIFICE. the King James Version frequently translates Hebrew shoq, literally, "leg," "thigh" (which see) by "shoulder," which the Revised Version (British and American) occasionally retains in the margin (e.g. Nu 6:20).