'Once' in the Bible

For when he died, he died once and for all as far as sin is concerned. But now that he is alive, he lives for God.

But thank God that, though you were once slaves of sin, you became obedient from your hearts to that form of teaching with which you were entrusted!

I am speaking in simple terms because of the frailty of your human nature. Just as you once offered the parts of your body as slaves to impurity and to greater and greater disobedience, so now, in the same way, you must offer the parts of your body as slaves to righteousness that leads to sanctification.