Romans 6:23 tells us that the wages of sin is death but the free gift of God is eternal life in Christ Jesus. It is interesting that Paul talks about the wages of sin, meaning that death is the due penalty for the horror of sin. Death is the apt reply to sin and the one who sins deserves to die. However eternal life is an altogether different matter. No one can ever deserve eternal life and no matter how hard you work for it, it is still a free gift because it is far too big for it to be anything other than a gift. Please note that we are not called to see eternal life as just a free handout to the casual passer by. There is an yielding to God and a presenting ourselves to Him as a total act of sacrifice. However, no matter whatever we do from our side, eternal life is still a free gift since our puny efforts are nothing when compared to the glory of this very life of God. All that we do is just make an undeserving move and what we get is the incomparable riches of eternal life.