זכריה ט:ט פירוש: רש״י

Behold! Your king shall come to you It is impossible to interpret this except as referring to the King Messiah, as it is stated: “and his rule shall be from sea to sea.” We do not find that Israel had such a ruler during the days of the Second Temple.

just and victorious saved by the Lord.

and riding a donkey This is a symbol of humility.