Got started on 2 Peter 1, and immediately noticed that the writer sounded like giving instructions to someone building a wall. Especially in 5-8. You take faith to moral excellence to knowledge then self-control to perseverance to godliness to brotherly kindness then love. He says that if these things or qualities are mine (yours) and are growing or increasing, then we are not “useless”. That sense of usefulness or uselessness has to do with the true knowledge of Jesus. You can’t have knowledge if you don’t study or attempt to learn!
Peter was talking to Christians who were falling prey to false teachers and were under great persecution by the Romans. Even before reading any thing else about these verses, it was clear to me that he was not advocating some steps to being a Christian – he was saying “now that you have this new life, work on all these things.” This was not head knowledge, but action – “while you practice (do) these things, you won’t stumble.” Check it out!