Philippians 3:12

Not that I have already obtained this or am already perfect, but I press on to make it my own, because Christ Jesus has made me his own. (Philippians 3:12, ESV)

Paul hasn't arrived.

It is quite possible that Paul has been in the Gospel Ministry for nearly 30 years at this point. And yet he still isn't there yet. He still isn't finished. God isn't done working on him. He has not attained a measure of "done-ness."

If Paul the Apostle takes this attitude to knowing Christ more... if 30-years-in-ministry-Paul takes this attitude to ongoing growth in the knowledge of Jesus Christ... How much more ought we?

So, what does Paul do? He presses on. He keeps at it. He keeps going forward.

D.A. Carson, in his commentary on Philippians, titled Basics for Believers, discusses Paul's continual pressing forward in his knowledge of Jesus by saying,

“Christians should never be satisfied with yesterday’s grace. It is a shocking thing for Christians to have to admit that they have grown little in their knowledge of Jesus Christ.” 

Notice that as Paul is continuing to press on to make Christ his own, it still isn't because he is seeking to earn or obtain a righteousness. In fact, he acknowledges that Christ has already handled that: Paul belongs to Christ.

You might say that his endeavors are now all about expanding his own understanding of what has already been done for him.