Jamieson, Fausset and Brown on Matthew 10:18

18. And ye shall be brought before governors--provincial rulers.

and kings--the highest tribunals.

for my sake, for a testimony against them--rather, "to them," in order to bear testimony to the truth and its glorious effects.

and the Gentiles--"to the Gentiles"; a hint that their message would not long be confined to the lost sheep of the house of Israel. The Acts of the Apostles are the best commentary on these warnings.