John Calvin explains justification as “the acceptance with which God receives us into his favor as righteous men. And we say that it consists in the remission of sins and the imputation of Christ’s righteousness.” Christ justifies no one whom he does not also sanctify. For these benefits have “an everlasting and indissoluble bond” in order that “those whom he illumines by his wisdom, he redeems; those whom he redeems, he justifies; those whom he justifies, he sanctifies.” Sanctification and justification are bestowed at the same time, never one without the other. Our union with Christ, by which we are justified, contains sanctification as well as righteousness. This is “a possibility which resides not in the man, but in God… In the definition, God reigns as the Divine Subject: God accepts us; God receives us into grace; God regards us as righteous. Justification is initiated and carried through by God and by God alone.”
I am convinced of the completeness of salvation (our justification by Christ’s death), but does Scripture attest to its permanency and absolute security of the believer?
Calvinists believe yes. For Calvin, our new birth in Christ and our inheritance is one that can “never perish, spoil, or fade – kept in heaven” for us, guarded by God’s own power. “The three adjectives used to describe our inheritance are vivid and powerful. They speak of our salvation as incapable of being destroyed in the fashion in which armies ravage a nation during war. It cannot be corrupted or spoiled by the introduction of something impure.” Jesus himself affirmed this by saying, “I give them eternal life, and they shall never perish; no one can snatch them out of my hand.” Calvin believes that if one has received eternal life, their salvation must be permanent. “If the elect could at some point lose your salvation, “God’s election of them to eternal life would not be truly effectual.” Spiritual death cannot occur. Eternal life has been given, and “eternal life is by definition everlasting.”
 Page 727, Institutes of the Christian Religion
 Page 798, Ibid.
 Page 98, Parker, Calvin: An Introduction to His Thought
 I Peter 1:3-9
 Page 998, Erickson, Christian Theology
 Page 1000, Erickson