And Jesus, when he had found a young ass, sat thereon; as it is written, John 12:14
The most natural points of comparison for Jesus’ work are found among these Jewish Messianic expectations. He rode into ‘his own city’ choosing a donkey as a sign of lowliness and subjection.
There is a hint in this which we find also discussed in the Talmud:
"The Son of David will come only in a generation which is either altogether righteous or altogether wicked.
‘In a generation which is altogether righteous;’ as it is written: ‘Then will your people be righteous and they will possess the land for ever’ (Is 60:21). Or ‘altogether wicked;’ as it is written: ‘He was that there was no-one, and he was appalled that there was no-one to intercede’ (Is 59:16)... ‘And behold, one like the son of man, coming in the clouds’ (Dan 7:13). It is also written, ‘gentle and riding on a donkey’ (Zech 9:9): if they are righteous he will come in the clouds. If not, he will come humbly and riding on a donkey."
(Santala, Risto. 1992. The Messiah in the Old Testament in the Light of Rabbinical Writings. Jerusalem: Yanetz Limited., pg 55)