Römer 6:6

Knowing this, &c.--The apostle now grows more definite and vivid in expressing the sin-destroying efficacy of our union with the crucified Saviour. that our old man--"our old selves"; that is, "all that we were in our old unregenerate condition, before union with Christ" (compare Col 3:9-10; Eph 4:22-24; Gal 2:20; Gal 5:24; Gal 6:14). is--rather, "was." crucified with him--in order. that the body of sin--not a figure for "the mass of sin"; nor the "material body," considered as the seat of sin, which it is not; but (as we judge) for "sin as it dwells in us in our present embodied state, under the law of the fall." might be destroyed--(in Christ's death)--to the end. that henceforth we should not serve sin--"be in bondage to sin."

The apostle having at large asserted, opened, and proved, the great doctrine of justification by faith, for fear lest any should suck poison out of that sweet flower, and turn that grace of God into wantonness and licentiousness, he, with a like zeal, copiousness of expression, and cogency of argument, presses the absolute necessity of sanctification and a holy life, as the inseparable fruit and companion of justification; for, wherever Jesus Christ is made of God unto any soul righteousness, he is made of God unto that soul sanctification, Co1 1:30. The water and the blood came streaming together out of the pierced side of the dying Jesus. And what God hath thus joined together let not us dare to put asunder.

6:6 our old sinful selves: Our “old selves” are not a nature that we possess or just one part of who we are; it reflects who we were in Adam. All human beings were born “in Adam.” As heirs of the sin and death that he introduced into the world (5:12), we were slaves to the power of sin. But as people who are now in Christ, we have gone through crucifixion with him (see also Gal 2:20). When he died on the cross, we also died to the dominating power of sin that ruled in our former selves.