Devices used to weigh an object by opposing it with a known weight. Balances or scales have been used to measure weight since at least the middle of the second millennium BC. Pictures and inscriptions in Egyptian tombs give us an idea of the appearance of the earliest scales. A pair of such balances found in Ugarit dates from about 1400 BC.
Balances usually consisted of four main parts: (1) an upright center standard, (2) a crossbar suspended from it, (3) two pans suspended from each end of the crossbar by cords, and (4) on the more elaborate models, a rod or pointer attached to the center of the crossbar at right angles to it. The rod moved in front of the standard so that when the two pans held equal weights the exact vertical position of the rod would be evident.
Scales or balances were used in the ancient world primarily to measure precious metals such as silver or gold. The Story of the Eloquent Peasant, dating from the Middle Kingdom of Egypt, however, mentioned the figurative measuring of a persons heart and tongue.
Balances are mentioned frequently in the OT, with much emphasis on the use of just weights in commerce (Leviticus 19:36; Proverbs 11:1; 16:11; 20:23; Ezekiel 45:10; Hosea 12:7; Amos 8:5; Micah 6:10-12). The weighing of silver with a balance is described (Isaiah 46:6), as when Jeremiah weighed the money that he paid for his nephews field (Jeremiah 32:8-10). In an acted-out prophecy, Ezekiel was told to cut off all his hair and beard and weigh it in balances to separate it into three equal parts (Ezekiel 5:1-2). Job asked to be weighed in a just balance, that God might know his integrity (Job 31:6). Daniel said that Belshazzar had been weighed in the balances (judged) and found wanting (Daniel 5:27). One reference to scales or balances is found in the NT, in Revelation 6:5, which speaks of a rider (on a black horse) having a balance in his hand. The prophecy is of severe famine, when some foods can no longer be obtained, when inflation has driven up food prices, and when people check the scales carefully to be sure they are not cheated when buying even the cheapest grains, such as barley (Revelation 6:6).