And let steadfastness have its full effect, that you may be perfect and complete, lacking in nothing. (ESV)
In the previous verse James told us that the testing of our faith produces steadfastness. We do not like testing. It involves pain and struggle. It challenges us. It hurts. While we do not like testing we have to recognize that our testing has a purpose. It produces steadfastness. This is a quality that the Lord wants his children to have.
This idea of steadfastness involves developing trust. With each trial we are forced to draw closer to God for the strength that we need to endure. With every trial that God brings us through we find that he is faithful. We realize that we can trust him in the next trial. We also show to our wonderful Savior that we can be trusted in the midst of the trials. Steadfastness. Demonstrated trusting relationship.
This steadfastness being worked in us through trials brings us to what James describes as us being "perfect and complete, lacking in nothing." Now, at first glance this seems like an impossibility. Is James suggesting that we can achieve perfection on earth? We should know that perfection while we have this sinful nature is not a reality.
This word for "perfect" means spiritual maturity. This is where so many in the church today are lacking. We have churches full of people who are spiritually immature, spending more time arguing with one another than sharing the Gospel. What is the solution? Trials. Testing. Steadfastness. It is the only way to maturity.
I am sure that you are facing some kind of trial. We all are. Use the time of trials to draw close to the Lord. Build that trust. Become steadfast. It is the way to spiritual maturity.