“Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall”
The word “sure,” means firm, steadfast, secure. Here, Peter is telling Christians to make it certain to themselves – not to God – that they had been chosen, and were truly called into the kingdom of God.
You’d subject yourself to needless battles of assurance of salvation if you don’t prove your calling. Also, you will not have a real sense of progress in your walk with God until you overcome some habits. Remember, God is telling you to do something that he has already empowered you to do.
“I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God” (Rom 12:1,2). And just before you think it is impossible to do this, you’re reminded in Ephesians 5:8: “For ye were sometimes darkness, but now are ye light in the Lord: walk as children of light.”
It is because you are now ‘light in the Lord’ that you can ‘prove’ or function in God’s perfect will (Eph 5:10, Rom 12:2). You have been called to function in agreement with God’s word concerning you. Exercise it in your life. Sanctification is the will of God. Exercise yourself in that will!
Spend time meditating on Ephesians 2:1-10 and Romans 6:1-14. Memorize as many portions as you can.