This passage is a confirmation and illustration of what the apostle had said before, Romans 6:5-7. The argument is, that as Christ was once dead but now lives to God, and will no more die, so we, being dead to sin, but living unto God, should not obey sin, but should live only to God.
Now if we be dead with Christ - If we be dead in a manner similar to what he was; if we are made dead to sin by his work, as he was dead in the grave; see the note at Romans 6:4.
We believe - All Christians. It is an article of our faith. This does not refer to the future world so much as to the present. It becomes an article of our belief that we are to live with Christ.
That we shall also live with him - This does not refer primarily to the resurrection, and to the future state, but to the present. “We hold it as an article of our faith, that we shall be alive with Christ.” As he was raised up from death, so we shall be raised from the death of sin. As he lives, so we shall live in holiness. We are in fact raised up here, and, as it were, made alive to him. This is not confined, however, to the present life, but as Christ lives forever, so the apostle goes on to show that we shall.
Knowing - As we all know. This is assumed as an undoubted article of belief.
Dieth no more - Will never die again. He will have occasion to make no other atonement for sin; for what he has made is sufficient for all. He is beyond the dominion of death, and will live forever, Revelation 1:18, “I am he that liveth and was dead, and behold I am alive forevermore.” This is not only a consolation to the Christian, but it is an argument why he should be holy.
No more dominion - No rule; no lordship; no power. He is free from its influence; and the king of terrors cannot reach his throne; compare Hebrews 9:25-28; Hebrews 10:12.
For in that he died - For in respect to the design of his death.
He died unto sin - His death had respect to sin. The design of his death was to destroy sin; to make an atonement for it, and thus to put it away. As his death was designed to effect this, so it follows that Christians being baptized into his death, and having it as their object to destroy sin, should not indulge in it. The whole force of the motive; therefore, drawn from the death of Christ, is to induce Christians to forsake sin; compare 2 Corinthians 5:15, “And that he died for all, that they which live should not henceforth, live unto themselves, but unto him which died for them and rose again.”
Once - ἐφάπαξ ephapax. Once only; once for all. This is an adverb denying a repetition (Schleusner), and implies that it will not be done again; compare Hebrews 7:27; Hebrews 9:12; Hebrews 10:10. The argument of the apostle rests much on this, that his death was once for all; that it would not be repeated.
In that he liveth - The object, the design of his living. He aims with his living power to promote the glory of God.
Unto God - He seeks to promote his glory. The argument of Paul is this: Christians by their profession are united to him. They are bound to imitate him. As he now lives only to advance the glory of God; as all his mighty power, now that he is raised from the dead, and elevated to his throne in heaven, is exerted to promote his glory; so should their powers, being raised from the death of sin, be exerted to promote the glory of God.
Likewise - In like manner. This is an exhortation drawn from the argument in the previous verses. It shows the design and tendency of the Christian scheme.
Reckon ye yourselves - Judge, or esteem yourselves.
To be dead indeed unto sin - So that sin shall have no influence or control ever you, any more than the objects of this world have ever the dead in their graves; see the note at Romans 6:2.
But alive unto God - Bound to live to promote his glory; to make this the great and sole object of your living.
Through Jesus Christ - By means of the death, and resurrection, and example of Jesus Christ. The apostle regards all our disposition to live to God as resulting from the work of the Lord Jesus Christ.