by J.I. Packer

For [God] says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” It does not, therefore, depend on man’s desire or effort, but on God’s mercy. ROMANS 9:15-16

The verb elect means “to select, or choose out.” The biblical doctrine of election is that before Creation God selected out of the human race, foreseen as fallen, those whom he would redeem, bring to faith, justify, and glorify in and through Jesus Christ (Rom. 8:28-39; Eph. 1:3-14; 2 Thess. 2:13-14; 2 Tim. 1:9-10). This divine choice is an expression of free and sovereign grace, for it is unconstrained and unconditional, not merited by anything in those who are its subjects. God owes sinners no mercy of any kind, only condemnation; so it is a wonder, and matter for endless praise, that he should choose to save any of us; and doubly so when his choice involved the giving of his own Son to suffer as sin-bearer for the elect (Rom. 8:32).

The doctrine of election, like every truth about God, involves mystery and sometimes stirs controversy. But in Scripture it is a pastoral doctrine, brought in to help Christians see how great is the grace that saves them, and to move them to humility, confidence, joy, praise, faithfulness, and holiness in response. It is the family secret of the children of God. We do not know who else he has chosen among those who do not yet believe, nor why it was his good pleasure to choose us in particular. What we do know is, first, that had we not been chosen for life we would not be believers now (for only the elect are brought to faith), and, second, that as elect believers we may rely on God to finish in us the good work that he started (1 Cor. 1:8-9; Phil. 1:6; 1 Thess. 5:23-24; 2 Tim. 1:12; 4:18). Knowledge of one’s election thus brings comfort and joy.

Peter tells us we should be “eager to make [our] calling and election sure” (2 Pet. 1:10)—that is, certain to us. Election is known by its fruits. Paul knew the election of the Thessalonians from their faith, hope, and love, the inward and outward transformation of their lives that the gospel had brought about (1 Thess. 1:3-6). The more that the qualities to which Peter has been exhorting his readers appear in our lives (goodness, knowledge, self-control, perseverance, godliness, brotherly kindness, love: 2 Pet. 1:5-7), the surer of our own election we are entitled to be.

The elect are, from one standpoint, the Father’s gift to the Son (John 6:39; 10:29; 17:2, 24). Jesus testifies that he came into this world specifically to save them (John 6:37-40; 10:14-16, 26-29; 15:16; 17:6-26; Eph. 5:25-27), and any account of his mission must emphasize this.

Reprobation is the name given to God’s eternal decision regarding those sinners whom he has not chosen for life. His decision is in essence a decision not to change them, as the elect are destined to be changed, but to leave them to sin as in their hearts they already want to do, and finally to judge them as they deserve for what they have done. When in particular instances God gives them over to their sins (i.e., removes restraints on their doing the disobedient things they desire), this is itself the beginning of judgment. It is called “hardening” (Rom. 9:18; 11:25; cf. Ps. 81:12; Rom. 1:24, 26, 28), and it inevitably leads to greater guilt.

Reprobation is a biblical reality (Rom. 9:14-24; 1 Pet. 2:8), but not one that bears directly on Christian behavior. The reprobates are faceless so far as Christians are concerned, and it is not for us to try to identify them. Rather, we should live in light of the certainty that anyone may be saved if he or she will but repent and put faith in Christ.

We should view all persons that we meet as possibly being numbered among the elect.

From: Concise Theology: A Guide To Historic Christian Beliefs