First, what Peter is NOT saying:
-You have to be perfect to be a Christian. (1 John 1:9)
-You better never sin or no Heaven for you. (Luke 23:39-43)
-You earn your way to eternal life. (Ephesians 2:8-9)
-If you sin it means you aren’t really saved. (2 Corinthians 12:9-11)
What Peter IS saying:
-You will be faced with evil desires and temptations.
-When you are tempted, do not conform to them. Do not obey them for they are no longer your master. (Romans 6:15-23; 1 Peter 2:9; John 8:11, etc.)
-Holiness is tapping into the power of Christ in you.
-You are not relying on your power and your strength to somehow rise above, but tapping into His power to refuse to conform to evil desires that well up in you.
-Holiness is not something you do, it is something you receive.