isaiah 42:6 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; - Free Bible Online

      6. in righteousness--rather, "for a righteous purpose" [LOWTH]. (See Isa 42:21). God "set forth" His Son "to be a propitiation (so as) to declare His (God's) righteousness, that God might be just, and (yet) the justifier of him which believeth in Jesus" (Ro 3:25, 26; compare see on Isa 41:2; Isa 45:13; 50:8, 9).
      hold . . . hand--compare as to Israel, the type of Messiah, Ho 11:3.
      covenant--the medium of the covenant, originally made between God and Abraham (Isa 49:8). "The mediator of a better covenant" (Heb 8:6) than the law (see Isa 49:8; Jer 31:33; 50:5). So the abstract "peace," for peace-maker (Mic 5:5; Eph 2:14).
      the people--Israel; as Isa 49:8, compared with Isa 42:6, proves (Lu 2:32).

JFB.