Monergism

"Jesus lived the life we should have lived, and died the death we should have died!" - Dr. Tim Keller

Calvin said, "Now someone asks, How has Christ abolished sin, banished the separation between us and God, and acquired righteousness to render God favorable and kindly toward us? To this we can in general reply that he has achieved this for us by the whole course of his obedience. This is proved by Paul’s testimony: “As by one man’s disobedience many were made sinners, so by one man’s obedience we are made righteous” [Romans 5:19]. In another passage, to be sure, Paul extends the basis of the pardon that frees us from the curse of the law to the whole life of Christ: “But when the fullness of time came, God sent forth his Son, born of woman, subject to the law, to redeem those who were under the law” [Galatians 4:4-5]. Thus in his very baptism, also, he asserted that he fulfilled a part of righteousness in obediently carrying out his Father’s commandment [Matthew 3:15]. In short, from the time when he took on the form of a servant, he began to pay the price of liberation in order to redeem us.

Yet to define the way of salvation more exactly, Scripture ascribes this as peculiar and proper to Christ’s death. He declares that “he gave his life to redeem many” [Matthew 20:28]. Paul teaches that “Christ died for our sins” [Romans 4:25]. John the Baptist proclaimed that he came “to take away the sins of the world,” for he was “the Lamb of God” [John 1:29]. In another passage Paul teaches that “we are freely justified through the redemption which is in Christ, because he was put forward as a reconciler in his blood” [Romans 3:24-25]. Likewise: “We are …justified by his blood …and reconciled …through his death.” [Romans 5:9-10.] Again: “For our sake he who knew no sin was made sin, so that in him we might become the righteousness of God.” [2 Corinthians 5:21] I shall not pursue all the testimonies, for the list would be endless, and many of them will be referred to in their order. For this reason the so-called “Apostles’ Creed” passes at once in the best order from the birth of Christ to his death and resurrection, wherein the whole of perfect salvation consists. Yet the remainder of the obedience that he manifested in his life is not excluded. Paul embraces it all from beginning to end: “He emptied himself, taking the form of a servant …and was obedient to the Father unto death, even death on a cross” - Calvin's Institutes 2.16.5

"...the Lord Christ fulfilled the whole law for us; He did not only undergo the penalty of it due unto our sins, but also yielded that perfect obedience which it did require... Christ's fulfilling of the law, in obedience unto its commands, is no less imputed unto us for our justification than His undergoing the penalty of it is." - John Owen The righteousness which is of the law (Lev 18:5 & Rom. 10:5) is a righteousness which is based upon and demands perfect and entire obedience to all the commands of God's law (Wilckens). Thanks be to God who sent His Son Jesus who did this very thing... "fulfilling the law" for us (living the life we should have lived), and dying the death we deserve, doing for us what we could not do for ourselves. "...Law righteousness" (Rom 10:5) comes through human performance or activity as its basis or ground, but the "righteousness by faith" (Rom 10:6) is a righteousnes that is exclusive of human endeavor and is received through faith." (Guy Waters) The former is an impossible supposition after "the fall" (But God's demand for perfection has not changed), and the later is made a reality because Christ fulfilled all righteousness on our behalf. The Scripture says as a human being "because of his reverence. ...he learned obedience ... And being made perfect, he became the source of eternal salvation to all who obey him, being designated by God a high priest after the order of Melchizedek." Heb 5:9-10

Dr. Robert L. Reymond defines the active obedience of Christ as:
“Christ’s full obedience to all the prescriptions of the divine law…[making] available a perfect righteousness before the law that is imputed or reckoned to those who put their trust in him.

Dr. Robert L. Reymond defines the passive obedience of Christ as:
“[Christ's] willing obedience in bearing all the sanctions imposed by that law against his people because of their transgression…[being] the ground of God’s justification of sinners (Rom. 5:9), by which divine act they are pardoned…”