There are at least two ways this verse is misused in gospel presentations. Before I mention them, it is worth noting that this is a verse written to Christians. I affirm using this verse in evangelism to non-Christians, but Paul does write this to Christians, so our first instinct should be to figure out how it applies to Christians:
- “For the wages of sin is death” is as much a warning to the believer against perservering in sin as it is to the non-Christian that he/she will receive death as a result of sin. Right before this Paul mentions “the end of [sin] is death” and sanctification has as “its end, eternal life.” Rom 6.23 is more a call to perseverance than a call to a one-time decision. A lot of this chapter is an attempt to persuade believers that since they are dead to sin, they should not produce fuits of darkness. No one should feel confident that they are a believer if they are presenting their body for works of the flesh all the time. ‘For the wages of sin is death.’
- “But the free gift of God is eternal life in Christ Jesus our Lord” should never be preached as a gift that can be rejected. Obviously, people can reject Jesus (but we should make it clear it is Jesus they are rejecting, not just eternal life). But the point of this verse is that God has freely given eternal life to believers! Eternal life is not something someone can reject now and it will be there for them later on when they want to accept it. Though the believer had lived his/her whole life trespassing against God (Rom 5.16), not getting any real fruit from those things (Rom 6.21), yet, God who is rich in mercy gave you freely in Christ eternal life.
So in summary, please do not call people to make decisions, but preach the gospel, and call people to a lifetime of perseverance. And do not offer eternal life to people as something people can accept or reject, but preach the gospel, and call people to a lifetime of perseverance.