Matthew equates the words of the prophets by placing kingship and salvation in one person, the humble man riding on a donkey, riding into a great city, where the king knows he will be murdered. Yes, murdered! It is the king who brings salvation, and it is the king who himself is salvation, but it is not the salvation (victory) wrought over the political enemies of Israel by means of military force.
1. Dictionary of Biblical Imagry, Intervarsity Press, p.215.