John Calvin Commentary Romans 6:22

"But now being made free from sin and become servants to God, ye have your fruit unto sanctification, and the end eternal life." — Romans 6:22 (ASV)

Ye have your fruit unto holiness, etc. As he had before mentioned a twofold end of sin, so he does now regarding righteousness. Sin in this life brings the torments of an accusing conscience, and in the next, eternal death. We now gather the fruit of righteousness, which is holiness; we hope in the future to gain eternal life. These things, unless we are utterly foolish, should create in our minds a hatred and horror of sin, and also a love and desire for righteousness.

Some translate τέλος as "tribute" or reward, and not "end," but this is not, as I think, according to the Apostle’s meaning; for although it is true that we bear the punishment of death on account of sin, this word is not suitable for the other clause to which Paul applies it, since life cannot be said to be the tribute or reward of righteousness.