II Peter 1
“Therefore, brethren, be all the more diligent to make certain about His calling and choosing you” (1:10). At first glance, this is a strange command, because it mixes God’s initiative (calling and choosing) with our responsibility (be diligent). However, this cooperation is at the heart of the good news. Peter says that God has “granted to us everything pertaining to life and godliness” and “His precious and magnificent promises” (v3-4).
Receiving these gifts, we respond by pressing on toward maturity, making the choices (moral excellence, self-control, etc, v5-7) which make us useful and fruitful in God’s kingdom (v8).