Death no more rules over him, etc. He seems to imply that death once ruled over Christ; and indeed when he gave himself up to death for us, he in a manner surrendered and subjected himself to its power; it was however in such a way that it was impossible that he should be kept bound by its pangs, so as to succumb to or to be swallowed up by them. He, therefore, by submitting to its dominion, as it were, for a moment, destroyed it for ever. Yet, to speak more simply, the dominion of death is to be referred to the state of death voluntarily undergone, which the resurrection terminated. The meaning is, that Christ, who now vivifies the faithful by his Spirit, or breathes his own life into them by his secret power from heaven, was freed from the dominion of death when he arose, that by virtue of the same dominion he might render free all his people.

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.

Christ being raised from the dead dieth no more - So we, believing in Christ Jesus, and having a death unto sin, and a life unto righteousness, should sin no more. If we be risen indeed with Christ, we should seek the things above, and set our affections on things above, and not on the earth. The man who walks in humble, loving obedience, to an indwelling Christ, sin has no more dominion over his soul than death has over the immortal and glorified body of his Redeemer.

Knowing that Christ being raised from the dead,.... That Christ is risen from the dead, is a certain fact, well attested, thoroughly known, and firmly believed; the prophets prophesied of it, Christ himself foretold it, angels affirmed it, and the apostles were witnesses of it, as is also the Holy Ghost: and it is as certain, that he
dieth no more; he is raised to an immortal life, and will live for evermore; there is no need of his dying again, his death having been a full atonement and expiation of all the sins and transgressions of his people:
death hath no more dominion over him: it once had dominion over him; it held him under its power for a time, according to the divine determination, and by his own consent: but it was not possible he should be holden of it longer; both on account of the dignity of his person, as the Son of God, and the virtue and efficacy of his sacrifice, as the surety of his people, having put away sin for ever by it. He is the holy man the Jews (u) speak of,
"who is the mystery of the name Jehovah, and in him there is no sin, neither shall death have the dominion over him.''
(u) Tikkune Zohar, fol. 112. p. 1. apud Rittangel. de verit. Relig. Christ. p. 68.

Christ being raised from the dead dieth no more; death hath no more dominion over him--Though Christ's death was in the most absolute sense a voluntary act (John 10:17-18; Acts 2:24), that voluntary surrender gave death such rightful "dominion over Him" as dissolved its dominion over us. But this once past, "death hath," even in that sense, "dominion over Him no more."