A verse tucked into the 2nd chapter of Colossians should be in our thoughts often, if not daily. Colossians 2:10 records, “and you are complete in Him, who is the head of all principality and power.” Chapter 2 of that book speaks of the sufficiency of Jesus.
My New King James Bible has section headings in that chapter such as “Not Philosophy but Christ” and “Not Legalism but Christ” and the start of chapter 3 is “Not Carnality but Christ.” The first part of the chapter warns about people who might try to come across as wise with philosophies that give the appearance of superiority but are in conflict with Jesus. To this Paul answers that we are complete in Him. We don’t need the wisdom of the world. Now we surely benefit from the knowledge of the world which scientists, doctors, horticulturalists, etc have gained but Christ is all we need for salvation and godly living.
Then Paul speaks about those who present a false religion of rules, which we would call legalism. He says in verse 21, “these things indeed have an appearance of wisdom in self-imposed religion, false humility and neglect of the body, but are of no value against the indulgence of the flesh.”
The next time you are tempted to doubt your salvation, which really amounts to doubting if Jesus’ work on the cross was sufficient, read chapter 2 where you are reminded of the death, burial, and resurrection of Jesus whereby the requirements of the law were nailed to the cross. We can put off the old man and put on the new man because “you died, and your life is hidden with Christ in God.” (3:3)
So friends, as Paul said in Romans 8:37, “we are more than conquerors through Him who loved us.”