That is, God treated Him as if He were a sinner, which He was not (see DA 25). The truths stated in v. 21 are among the most profound and significant in all the Bible. This verse sums up the plan of salvation, declaring the absolute sinlessness of Christ, the vicarious nature of His sacrifice, and man’s freedom from sin through Him. See on John 3:16.

 How Jesus could come to this world as a human being and “in all points” be “tempted like as we are, yet without sin” (Heb. 4:15) is an unfathomable mystery. He never committed sin, in word, in thought, or in deed. Throughout the entire course of His life He kept Himself from sin in every way. Here on earth He lived a holy, undefiled, and pure life, ever conscious of being in harmony with the Father’s will (John 8:46; 14:30; 15:10; Heb. 7:26; see Additional Note on John 1; see on Luke 2:52). Christ, the Sinless One, took sinful humanity to His warm heart of love and experienced the temptations that beset us without being in the least degree overcome by them. He “identified Himself with sinners” (DA 111). When, on the cross, Jesus came to the hour for which He had entered the world (John 8:20; 12:23, 27; 13:1; 17:1; 18:37), He was “offered to bear the sins of many” (Heb. 9:28) and became the “Lamb of God, which taketh away the sin of the world” (John 1:29).

 The guilt of the sins of the world was reckoned to Him as if it were all His own (Isa. 53:3-6; 1 Peter 2:22-24). “He was numbered with the transgressors” (Mark 15:28). Christ became identified with sin; He took it to Himself in a real sense and felt the horror of separation from God.

 See on Rom. 5:19. As our sins were reckoned to Christ, as if they were His, so His rightheouness is reckoned to us as if it were ours.