What are the three duties of Christ?

The three positions of Christ are prophet, priest and king.

The prophet sends a message to people on behalf of God, and Jesus sent a message of repentance to people during his lifetime, "The kingdom of heaven is near, so you should repent".

Priests appeal to God instead of people,

Kings rule over all things on behalf of God.

Deut 18:15 The Lord your God will raise up for you a prophet like me from among your brothers, and you shall listen to him.

matt 2:6 o Bethlehem in the land of Judah, you are not the smallest among the cities of Judah, for a king will come out of you to shepherd my people Israel.

Hebrews 4:14 Since we have a high priest who has ascended to heaven, that is, Jesus, the son of God, we should hold fast to the acknowledged word.