Schaff's Bible Dictionary
HARDNESS, 1 Kgs 20:11. In this passage and some others the word denotes armor. The phrase "made ready his chariot," Ex 14:6, literally means, in modern phraseology, "tackled," or "put to, his horses." That bridles with bits were very early known as part of the harness of a horse is obvious from Isa 37:29; Prov 26:3; Ps 32:9. The ancient harness was often very elaborate, as the monuments testify.