Therefore I intend always to remind you of these qualities, though you know them and are established in the truth that you have. (2 Peter 1:12)
The apostle Peter writes to Christians who do know a lot already from his previous letter, and have also received teaching from others. The purpose of his letter is not just to explain new things, but also to remind them of important themes they already know. The apostle Paul did the same in his letters: “To write the same things to you is no trouble to me and is safe for you.” (Philippians 3:1) “On some points I have written to you very boldly by way of reminder.” (Romans 15:15) Some things are just too important to forget. Peter wants his addressees to “be able at any time to recall these things.” (2 Peter 1:15) This is necessary to discern false beliefs or misleading teachings that are not in line with the Gospel.
If we want to be “established in the truth”, we should read and reread the Bible. We should carefully study it. And if we hear new teachings or new interpretations of certain doctrines, we should examine the Scriptures to see if these things are correct. This guards against being led astray.
Do you have a sound knowledge of key themes of the Christian faith?