Barnes New Testament Notes

Verse 18. Being then made free from sin. That is, as a master. You are not under its dominion; you are no longer its slaves. They were made free, as a servant is who is set at liberty, and who is, therefore, no longer under obligation to obey.

Ye became the servants, etc. You became voluntarily under the dominion of righteousness; you yielded yourselves to it; and are therefore bound to be holy. Comp. See Barnes "Joh 8:32".

{a} "free from sin" Joh 8:32