Romans 6:10

For in that he died, he died unto sin once: but in that he liveth, he liveth unto God.

For in that he died, [ ho (G3739) gar (G1063) apethanen (G599)]. The strict rendering (as Fritzsche shows) is, 'The death which He died.'

He died unto (that is, in obedience to the claims of) sin once [ ef' (G1909) hapax (G530)] - 'once for all;' as Hebrews 7:27; Hebrews 9:12; Hebrews 10:10:

But in that he liveth, he liveth unto (in obedience to the claims of) 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" (Isaiah 53:6; 2 Corinthians 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.