The free gift is righteousness, that’s why a believer now has eternal life.
“For if, by the trespass of the one man, death reigned through that one man, how much more will those who receive God’s abundant provision of grace and of the gift of righteousness reign in life through the one man, Jesus Christ! Consequently, just as one trespass resulted in condemnation for all people, so also one righteous act resulted in justification and life for all people. For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous.
The law was brought in so that the trespass might increase. But where sin increased, grace increased all the more, so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord.” Rom 5:17-21
“What benefit did you reap at that time from the things you are now ashamed of? Those things result in death! But now that you have been set free from sin and have become slaves of God, the benefit you reap leads to holiness, and the result is eternal life.” Rom 6:22
Again, a gospel that separates the need for man to be righteous, walking as a child of God should, from the realization of eternal life, is novel, false, and could only come from the evil one. There’s no question that we’re forgiven. But that’s only meaningful for one who cares, who responds, who turns to Him as a result. That person is washed, cleansed, made new a creation, a slave to righteousness, able to ‘ go, and sin no more’. So what are we going to do with this forgiveness, this grace?
“For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins.” Matt 6:14-15