We’re to give diligence concerning the promises he just mentioned in verses 3-4 which says that His power gives us all things that pertain to life and godliness through the knowledge of Him.  By His exceeding great and precious promises you can partake of His divine nature.  And having that nature is the thing that keeps you out of the devil's reach.  You’re to give diligence in this area of knowledge of Him and of what His power and His promises bring, (which is partaking of His divine nature and all things that pertain to life and godliness).  Exercise your faith to develop virtue (courageous excellence) and exercise your virtue to develop knowledge.

Once you receive Jesus Christ and partake of the divine nature, you’re to be diligent and persistent in your Christian walk.  You need to pursue a greater personal knowledge of Him, a greater excellence in your intimacy and understanding with Him.  Don't sit back and neglect what He has made available to you.  There are exceeding great and precious promises He has provided!

Through His divine nature you escape the corruption in the world (verse 4).  Be diligent in your faith, virtue and knowledge in Him.

Confession:

I will be diligent in my Christian walk.  I will add virtue or courageous excellence to my faith and I will add knowledge to my virtue.