Herman Bavinck explains how Adam, in his pre-Fall state, lacked "absolute certainty" regarding his present state of bliss and its continuity, whereas the believer in Christ, now in this present sin-ravaged age, possesses it:
Still, on the other hand, the state of the first man should not be exaggeratedly glorified as is so often done in Christian doctrine and preaching. No matter how high God placed man above the animal level, man had not yet achieved his highest possible level. He was able-not-to-sin, but not yet not-able-to-sin. He did not yet possess eternal life which cannot be corrupted and cannot die, but received instead a preliminary immortality whose existence and duration depended upon the fulfillment of a condition. He was immediately created as image of God, but he could still lose this image and all its glory. He lived in paradise, it is true, but this paradise was not heaven and it could with all of its beauty be forfeited by him. One thing was lacking in all the riches, both spiritual and physical, which Adam possessed: absolute certainty. As long as we do not have that, our rest and our pleasure is not yet perfect; in fact, the contemporary world with its many efforts to insure everything that man possesses is satisfactory evidence for this. The believers are insured for this life and the next, for Christ is their Guarantor and will not allow any of them to be plucked out of His hand and be lost (John 10:28). Perfect love banishes fear in them (1 John 4:18) and persuades them that nothing shall separate them from the love of God which is in Christ Jesus their Lord (Rom. 8:38-39). But this absolute certainty was lacking to man in paradise; he was not, together with his creation in the image of God, permanently established in the good. Irrespective of how much he had, he could lose it all, both for himself and for his posterity. His origin was Divine; his nature was related to the Divine nature; his destiny was eternal blessedness in the immediate presence of God. But whether he was to reach that appointed destination was made dependent upon his own choice and upon his own will.
What then shall we say to these things? If God is for us, who can be against us? He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things? Who shall bring any charge against God's elect? It is God who justifies. Who is to condemn? Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us. Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or danger, or sword? As it is written, 'For your sake we are being killed all the day long; we are regarded as sheep to be slaughtered.' No, in all these things we are more than conquerors through him who loved us. For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord. (Romans 8:31-39)
What a Gospel!