One of my most unfavourite stupid human arguments of all time this one!
Humanity was given the law as well as the punishments for breaking those laws via the Jew's when He made the old covenant with them.
Then when Jesus came along, He did away with the old covenant and also spoke about true justice.
Mat 23:23 Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone.
Plus Paul has something to say about that blows their stupid argument out of the water!
Rom 6:23 For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
Rom 1:27 And likewise also the men, leaving the natural use of the woman, burned in their lust toward one another; males with males working out shamefulness, and receiving in themselves the recompense which was fitting for their error.
First of all, He says the wages of sin is death, not eternal punishment, and then He says that they already received that punishment that was due them.
Nowhere in the entire bible does God or anyone else say anything about the wages of sin being eternal punishment and the next time someone say otherwise, you can ask them to show you a verse that says that the penalty for sin is everlasting punishment.
I guarantee that they won't be able to present you with that scripture.