Ass in Wikipedia
The ass has always enjoyed a marked favour above all other beasts of burden in the bible. This is evidenced by two very simple remarks. While, on the one hand, mention of this animal occurs over a hundred and thirty times in Bible. On the other hand, the Hebrew vocabulary possesses, to designate the ass, according to its colour, sex, age, etc., a supply of words in striking contrast with the ordinary penury of the sacred language. Of these various names the most common is hamôr, "reddish", the hair of the Eastern ass being generally of that colour. White asses, more rare, were also more appreciated and reserved for the use of the nobles (Judges 5:10). The custom was introduced very early, as it seems, and still prevails, to paint the most shapely and valuable donkeys in stripes of different colours. In the East the ass is much larger and finer than in other countries, and in several places the pedigrees of the best breeds are carefully preserved. Asses have always been an important item in the resources of the Eastern peoples, and we are repeatedly told in the Bible about the herds of these animals owned by the patriarchs (Genesis 12:16; 30:43; 36:24, etc.), and wealthy Israelites (1 Samuel 9:3; 1 Chronicles 27:30, etc.). Hence the several regulations brought forth by Israel's lawgiver on this subject: the neighbour's ass should not be coveted (Exodus 20:17); moreover, should the neighbour's stray ass be found, it should be taken care of, and its owner assisted in tending this part of his herd (Deuteronomy 22:3, 4). The ass serves in the East for many purposes. Its even gait and surefootedness, so well suited to the rough paths of the Holy Land, made it at all times the most popular of all the animals for riding in those hilly regions (Genesis 22:3; Luke 19:30). Neither was it ridden only by the common people, but also by persons of the highest rank (Judges 5:10; 10:4; 2 Samuel 17:23; 19:26, etc.). No wonder therefore that Jesus, about to come triumphantly to Jerusalem, commanded His disciples to bring Him an ass and her colt; no lesson of humility, as is sometimes asserted, but the affirmation of the peaceful character of His kingdom should be sought there. Although the Scripture speaks of "saddling" the ass, usually no saddle was used by the rider. A cloth was spread upon the back of the ass and fastened by a strap was all the equipment. Upon this cloth the rider sat with a servant usually walking alongside. Should a family journey, the women and children would ride the asses, attended by the father (Exodus 4:20). This mode of travelling has been popularized by Christian painters, who copied the eastern customs in their representations of the Holy Family's flight to Egypt.
Scores of passages in the Bible allude to asses carrying burdens. The Gospels, at least in the Greek text, speak of millstones run by asses (Matthew 18:6, Mark 9:41; Luke 17:2); Josephus and the Egyptian monuments teach us that this animal was used for threshing wheat. Finally, we repeatedly read in the Old Testament of asses hitched to a plough (Deuteronomy 22:10; Isaiah 30:24, etc.), and in reference to this custom, the Law forbade ploughing with an ox and an ass together (Deuteronomy 22:10). From Is., xxi, 7, confirmed by the statements of Greek writers, we learn that part of the cavalry force in the Persian army rode donkeys. We should perhaps understand from IV K., vii, 7, that the Syrian armies followed the same practice; but no such custom seems to have ever prevailed among the Hebrews. With them the ass was essentially for peaceful use, the emblem of peace, as the horse was the symbol of war. The flesh of the donkey was unclean and forbidden by the Law. In some particular circumstances, however, no law could prevail over necessity, and we read that during Joram's reign, when Benadad besieged Samaria, the famine was so extreme in this city, that the head of an ass was sold for 120 pieces of silver (IV K., vi, 25).