Diligence: Peter sees diligence as a necessary means of sanctification. Divine power is available to God’s people (1:3), but we must utilize it with diligence. If the compressor is full, the batteries are charged, and the tanks are filled, but the construction workers just sit idly about, no house will ever get built. Likewise, the provision for godliness by itself does not produce godliness. God calls us to labor toward holiness (Phil. 2:12). Peter points out seven areas of our spiritual labor: moral excellence, knowledge, self-control, perseverance, godliness, brotherly kindness, and love.[1] We are to build these virtues. There is no room for complacency (Phil. 3:12-13). No lazy person is much sanctified.

Assurance: Peter ties our sanctification to our subjective assurance. The basis for our objective assurance of salvation is the substitutionary atonement of Christ (1 Pet. 2:24; Rom. 5:9-10). But since these are given to us by means of faith, our subjective assurance is experienced to the degree that we can know that we possess genuine faith. In his first epistle, Peter pointed to the evidence of passing the test of trials (1 Pet. 1:6-9), here he points to the evidence of our positive spiritual growth (or sanctification). This second evidence resounds throughout the New Testament.[2] To the degree that we exhibit a likeness to Christ, our assurance grows because we can see that our faith is real and fruit-bearing. Peter, thus, challenges us to be diligent toward continued spiritual growth, because much fruit brings about much assurance (John 15:8).

[1] These are not meant to be exhaustive, as they leave out some of the fruit of the Spirit (Gal. 5:22-23). Also, the favored description for sanctification in the NT is conformity to Christ (Rom. 8:29; Eph. 4:13; 1 John 2:6; 3:3, 7). Peter highlights these seven; but, needless to say, there is more to sanctification than these virtues alone.

[2] Cf. Rom. 6:22-23; 8:1-8; Gal. 6:8; James 2:26; 1 John 2:3-4, 29; 3:8-10. As stated above, this is seen in our conformity to Christ. This is how true disciples are known (John 13:34-35).