One of the most comforting truths in Scripture is the fact that Christ not only died for the sins of his people but also obeyed the law on their behalf. In Reformed theological terms, we call this the active and passive obedience of Christ. Christ, as the second Adam, kept the covenant of works, earning the reward of eternal life for his people. He also died on the cross to bear the curse his people deserved and the result was complete forgiveness of sins. As J. G. Machen said, “He was…our representative both in penalty paying and in probation keeping. He paid the penalty of sin for us, and he stood the probation for us.” Jesus paid for our sin and obeyed the law; thus we are righteous in God’s sight by faith alone in Christ alone by grace alone. Here’s how Machen described Christ’s obedience (active and passive) using a dialogue between the law and the redeemed sinner.
‘Man,’ says the law of God, ‘have you obeyed my commands?’
‘No,’ says the sinner saved by grace. ‘I have disobeyed them, not only in the person of my representative Adam in his first sin, but also in that I myself have sinned in thought, word, and deed.’
‘Well then, sinner,’ says the law of God, ‘have you paid the penalty which I pronounced upon disobedience?’
‘No,’ says the sinner, ‘I have not paid the penalty myself; but Christ has paid it for me. He was my representative when he died there on the cross. Hence, so far as the penalty is concerned, I am clear.’
‘Well then, sinner,’ says the law of God, ‘how about the conditions which God has pronounced for the attainment of assured blessedness? Have you stood the test? Have you merited eternal life by perfect obedience during the period of probation?’
‘No’,’ says the sinner, ‘I have not merited eternal life by my own perfect obedience. God knows and my own conscience knows that even after I became a Christian I have sinned in thought, word, and deed. But although I have not merited eternal life by any obedience of my own, Christ has merited it for me by his perfect obedience. He was not for himself subject to the law. No obedience was required of him for himself, since he was Lord of all. That obedience, then, which he rendered to the law when he was on earth, was rendered by him as my representative. I have no righteousness of my own, but clad in Christ’s perfect righteousness, imputed to me and received by faith alone, I can glory in the fact that so far as I am concerned the probation has been kept and as God is true there awaits me the glorious reward which Christ thus earned for me.’”
You can find this and other outstanding articles by Machen in God Transcendent (Banner of Truth: Edinburgh, 1982). FYI, Machen penned these words on the active obedience of Christ very soon before he spoke those wonderful words on his death bed: “Grateful for the active obedience of Christ – no hope without it.”