Albert Barnes Commentary Matthew 12:18

"Behold, my servant whom I have chosen; My beloved in whom my soul is well pleased: I will put my Spirit upon him, And he shall declare judgment to the Gentiles." — Matthew 12:18 (ASV)

My servant. This refers to the Messiah, the Lord Jesus, who is called a servant because he took the form of a servant—meaning he was born in a humble condition (Philippians 2:7)—and because he obeyed or served God .

Shall show judgment to the Gentiles. The word judgment means, in Hebrew, law, commands, and so on (Psalms 19:9; Psalms 119:29–30).

It means the whole system of truth: the law of God in general; the purpose, plan, or judgment of God concerning human duty and conduct. In this context, it evidently means the system of gospel truth, the Christian scheme.

Gentiles. This refers to all who were not Jews. This prophecy was fulfilled by the multitudes coming to him from Idumea, from beyond the Jordan, and from Tyre and Sidon, as recorded in Mark 3:7-8.