FOR THE WAGES OF SIN IS DEATH; BUT THE GIFT OF GOD IS ETERNAL LIFE THROUGH JESUS CHRIST OUR LORD.
Wages Of Sin
God uses two contrasting words, "wages" and "gift." Wages are earned by our labor and a gift is received without labor. Most people who believe in God and an Afterlife believe that they must labor in some way to earn heaven but God says this labor only earns us death because our labor is marred by sin. This death means, "A Separation," specifically separation from God for all eternity in Hell.
The Gift of God
Rather than separation from God, He wants us to be eternally with Him. He in fact makes this as easy as he possibly could, by a gift. Eternal life is certainly unearned but is rather Given by God because of his perfect love for us. This gift, though free for us, is not free. This gift was bought with a great price...
Through Jesus Christ
Jesus Christ came in the flesh in order to die a brutal and bloody death in order to pay the penalty for our sin. we broke God's Laws but Jesus paid the penalty that we deserve. To refuse this great gift makes no sense, yet so many do and continue trying to earn their way to God and heaven. It is only by faith in Jesus Christ, who is God, who died for our sin, who rose from the dead that we can get to God and heaven.