Throughout the Word of God we are constantly assured of two facts. First, if anyone goes to hell, it is his fault, his own responsibility, altogether the result of what he has done, and that for which he alone must bear the blame forever. Second, if anyone is saved, if anyone goes to heaven, it is God's fault, altogether the result of that which God has done, and that for which God alone must have the praise forever.
The Wages of Sin
"the wages of sin is death!" -- Sin is what we all are by nature; and sin is all that we do in a state of rebellion against God. It is as impossible for a sinner to do good as it is for water to be dry. Our corrupt nature corrupts all our thoughts, feelings, words, and deeds. As a corrupt fountain only brings forth corrupt water, so a corrupt heart only brings forth corruption. That means that the very plowing of the wicked is an abomination to God, and even our righteousnesses are filthy rags in his sight (Pro. 21:4; Isa. 64:6). Sin is also our choice. We all drink iniquity like water (Job 15:16). And that which sin deserves is death, eternal death, which is eternal separation from God and the eternal vengeance of his holy wrath. Death is the debt God owes to sin. And God always pays his debts.
The Gift of God
"But the gift of God is eternal life!" -- Eternal life comes to guilty sinners not as a debt, or a reward for something we have done, but as the free grace gift of God. The new birth, which is the beginning of eternal life in the soul, is the gift of God. Heavenly glory, which is the consummation of eternal life, is also the gift of God. Death, hell, and judgment are things we earn by sin. But grace, life, and heaven are things freely given to sinners.
"Through Jesus Christ our Lord!" -- Christ, having paid the debt of sin for his people by his death upon the cross, has made it right and just for the holy Lord God, who must punish sin, to give eternal life to all for whom he died. Through the merits of Christ, through his blood and righteousness, God gives eternal life to everyone who believes on him. Even the faith by which we receive this gift is the gift of God and the result of his operation of grace (Eph. 2:8; Col. 1:12). Faith in Christ is not the cause of God's gift, but the result of it. If you now believe on the Lord Jesus Christ, God has given you eternal life! It is altogether his work! "Salvation is of the Lord!"