How can I be sure that I am elect, as Peter exhorts me here? Just as it was a knowledge of self that caused me to run to Christ, so it is also, in part, that confirms in me that I am in Christ. I knew I was a sinner and ran to Christ … I know now that I hate sin and love my Saviour … I know also that I am progressing in Christian graces. These things, not just tacked onto life but in me confirmed in my soul, by the Holy Spirit, that I am His and He is mind.
Peter calls us to take a spiritual inventory, to look for evidences of a changed heart, and for graces to increase in the life (Vs. 8). If these things are in us, we will be effective and fruitful in our Christian calling (Vs. 8) and we shall not fall into habitual sin, which brings us down to perdition (Vs. 10).
Notice also, that these Christian qualities are provided for us in Christ (Vs. 11), that it is the function of the Church to remind us of and provoke us in these qualities, (Vs. 12 cf. Hebrews 3:13, 10:25), that we might not prove ourselves to be apostate.