8 Yet indeed I also count all things loss for the excellence of the knowledge of Christ Jesus my Lord, for whom I have suffered the loss of all things, and count them as rubbish, that I may gain Christ
9 and be found in Him, not having my own righteousness, which is from the law, but that which is through faith in Christ, the righteousness which is from God by faith;
In verse 9 the phrase “be found in Him” means to obtain Christ. When we put our faith in Jesus we should no longer strive to obtain things, or human status, we have obtained all we need in Christ Jesus our Lord. Our sole worth in life should now only be found in Him and nothing else, and like the apostle Paul we should count all things loss and focus on knowing Jesus. Paul knew something about pursuing the wrong things in life.
From an early age Paul thought what he was pursuing in life was the right thing. Raised in a culture where knowing and keeping what had become a man-made religion, as the Jews had added many of their own laws to what God had given to them, this was considered a life to be envied. It was a deceiving way to live life thinking if you could live up to the standards that man had made, you could become righteous and know God. Paul upon meeting Jesus on the Damascus road found out he had placed his value in life on the wrong thing.
Many believers still do so today. They may value their possessions, money, or their status in a position as something to chase after. Paul found out all such things including man-made religion were as rubbish compared to knowing Jesus, for they cannot give you what really matters in life, being found in Him. It comes from faith in Christ, and a daily pursuit of knowing Him. All other things will simply leave you empty. But knowing Jesus personally and pursuing Him will fill your life to the full, to overflowing.