2 Peter 1:10: Therefore, Brothers, Be All The More Diligent To Confirm Your Calling And Election, For If You Practice These Qualities You Will Never Fall.
As we see the word, "therefore," we need to look back at the previous verses. Peter has just given instruction on how we are to live our lives as believers in Jesus Christ. He talked about all of the godly qualities that should be added to the faith that we received. We were told that we should "make every effort" to add these qualities to our lives (2 Peter 1:5-9).
In light of all of the importance of having these godly qualities, we are to be more diligent to confirm our calling and election. All of those who are saved were called by God to be saved. They are the elect. Romans 8:30 reminds us: "And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified."
God has done his work by calling us unto himself. Jesus, at the cross, made the way possible for our justification (being made right with God in our sinful state). He will glorify all of those whom he chose. That is God's work. We also have a work. We are to be diligent to confirm our calling and election. Peter is not saying that we do anything to save ourselves from sin.
We practice the qualities that Peter listed (virtue, knowledge, self-control, steadfastness, godliness, brotherly affection, and love). The practice of these qualities gives us assurance that we are God's elect. Peter says that if we practice them we will not fall. In other words, we will not be overcome by doubt and discouragement. We will know that we are walking in God's ways, and belonging to him.
Sometimes we face doubt and discouragement in our faith, and it is because we are not walking in the way that God called us to walk. If you are God's chosen child, act in the ways that he calls you to act. You will be filled with assurance and comfort.