1 Samuel 16:3

And thou shalt anoint. — From very early times the ceremony of anointing to important offices was customary among the Hebrews. In the first instance, all the priests were anointed (Exodus 40:15; Numbers 3:3), but afterwards anointing seems to have been reserved especially for the high priest (Exodus 29:29). Prophets also seem occasionally to have been anointed to their holy office. Anointing, however, was the principal ceremony in the inauguration of the Hebrew kings. It belonged in so especial a manner to the royal functions that the favourite designation for the king in Israel was “the Lord’s anointed.” In the case of David, the ceremony of anointing was performed three times — (1) on this occasion by Samuel, when the boy was set apart for the service of the Lord; (2) when appointed king over Judah at Hebron (2 Samuel 2:4); (3) when chosen as monarch over all Israel (2 Samuel 5:3). All these official personages, the priest, the prophet, and peculiarly the king, were types of the great expected Deliverer, ever known as the “Messiah,” “the Christ,” “the Anointed One.”

Wordsworth curiously considers these three successive unctions of David figurative of the successive unctions of Christ: conceived by the Holy Ghost in the Virgin’s womb; then anointed publicly at his baptism; and finally, set at God’s right hand as King of the Universal Church in the heavenly Jerusalem.