Have called thee in righteousness; to declare my righteousness, as is said, Romans 3:26, or my faithfulness, which is frequently called righteousness in Scripture; according to my promise long since made, and oft-renewed. As the former verse asserted God's power, so this clause declares his will and firm purpose and obligation to effect this work, and both together evince the certainty and necessity of it. Will hold thine hand; will give thee counsel and strength for thy high and hard work. Will keep thee, that thou shalt not fail in, nor be hindered by, thine enemies from the accomplishment of thy work. Give thee for a covenant; to be the Angel of the covenant, as Christ is called, Zechariah 3:1; or the Mediator, in and by whom my covenant of grace is made and confirmed with mankind. Of the people; either of my people, the Jews; or, indefinitely or universally, of all people, not only Jews, but Gentiles also, as it follows. For a light of the Gentiles; to enlighten them with true and saving knowledge, and to direct them in the right way to true happiness, from which they had miserably wandered. He alludes to God's fiery pillar, which enlightened and directed the Israelites in the wilderness.
Related Commentaries of Isaiah 42:6
Isaiah 42:6
6 I the LORD have called thee in righteousness, and will hold thine hand, and will keep thee, and give thee for a covenant of the people, for a light of the Gentiles;