50:4-9 As Jesus was God and man in one person, we find him sometimes speaking, or spoken of, as the Lord God; at other times, as man and the servant of Jehovah. He was to declare the truths which comfort the broken, contrite heart, those weary of sin, harassed with afflictions. And as the Holy Spirit was upon him, that he might speak as never man spake; so the same Divine influence daily wakened him to pray, to preach the gospel, and to receive and deliver the whole will of the Father. The Father justified the Son when he accepted the satisfaction he made for the sin of man. Christ speaks in the name of all believers. Who dares to be an enemy to those unto whom he is a Friend? or who will contend with those whom he is an Advocate? Thus St. Paul applies it, Ro 8:33.
8. (Isa 49:4). The believer, by virtue of his oneness with Christ, uses the same language (Ps 138:8; Ro 8:32-34). But "justify" in His case, is God's judicial acceptance and vindication of Him on the ground of His own righteousness (Lu 23:44-47; Ro 1:4; 1Ti 3:16, with which compare 1Pe 3:18); in their case, on the ground of His righteousness and meritorious death imputed to them (Ro 5:19).
stand together—in judgment, to try the issue.
adversary—literally, "master of my cause," that is, who has real ground of accusation against me, so that he can demand judgment to be given in his favor (compare Zec 3:1, &c. Re 12:10).