Römer 6:10

For in that he died, he died unto--that is, in obedience to the claims of sin once--for all. but in that he liveth, he liveth unto--in obedience to the claims of God. God--There never, indeed, was a time when Christ did not "live unto God." But in the days of His flesh He did so under the continual burden of sin "laid on Him" (Isa 53:6; Co2 5:21); whereas, now that He has "put away sin by the sacrifice of Himself," He "liveth unto God," the acquitted and accepted Surety, unchallenged and unclouded by the claims of 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.

6:10 he died once to break the power of sin: Because we died with Jesus (6:4-5), we have also died to sin (6:2). Jesus was never under sin’s power in the way that we are, because he had no sin nature from Adam and he never succumbed to temptation (2 Cor 5:21; Heb 4:15). However, when he became human, he entered the arena where sin holds sway, and he was truly vulnerable to sin.