Easton's Bible Dictionary

Mule - (Heb. pered), so called from the quick step of the animal or its power of carrying loads. It is not probable that the Hebrews bred mules, as this was strictly forbidden in the law (Lev. 19:19), although their use was not forbidden. We find them in common use even by kings and nobles (2 Sam. 18:9; 1 Kings 1:33; 2 Kings 5:17; Ps. 32:9). They are not mentioned, however, till the time of David, for the word rendered "mules" (R.V. correctly, "hot springs") in Gen. 36:24 (yemim) properly denotes the warm springs of Callirhoe, on the eastern shore of the Dead Sea. In David's reign they became very common (2 Sam. 13:29; 1 Kings 10:25).

Mules are not mentioned in the New Testament. Perhaps they had by that time ceased to be used in Palestine.