Zechariah 9:9 - 10
ESV - 9 Rejoice greatly, O daughter of Zion! Shout aloud, O daughter of Jerusalem! Behold, your king is coming to you; righteous and having salvation is he, humble and mounted on a donkey, on a colt, the foal of a donkey. 10 I will cut off the chariot from Ephraim and the war horse from Jerusalem; and the battle bow shall be cut off, and he shall speak peace to the nations; his rule shall be from sea to sea, and from the River to the ends of the earth.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Jesus Christ (God Incarnate) came as a baby and humble and rode a Donkey into Jerusalem to show He was the Son of man and to show us the nature of God. To know God is to know Jesus Christ who is one with the Holy Spirit. Jesus came to do the Will of the Father and died at the hands of men that He created.
But, He arose from the dead to right the wrong that men did at the Garden of Eden and He will give the believers eternal life. Soon in His timing, He will return on a Warhorse to judge mankind and will return as the King of Kings. Every knee will bow and every tounge confess that He is Lord. Praise be to God. If you don't know Him as Lord and Savior, there is still time for you to know the Creator of the Universe.
1st coming was on a donkey. 2nd coming will be on white horse. 1st coming as a suffering prophet. 2nd coming as a conquering king.