That the man of God may be perfect, thoroughly furnished unto all good works.
The Lord’s plan for His people is that they will do good works. But to be ready to do them we have to be in the right state - that is, we are living and behaving in the way God likes. If you read the prior verse (16) in your Bible you will see that we need all of Scripture and we need to apply it before we can be perfect (or mature) and ready for good works. Good works without a Godly life are wasted time. Live your life right before God first (starting NOW) - then you can serve properly.