Most of us probably think that we haven't lost anything by choosing to be a Christian.
Most of all Paul has lost his freedom, and lost it more than once as he was imprisoned more than once. He had been beaten and run out of town more than once. For most of us, this is not an issue.
Yes, some will lose friends, especially if they want us to participate in activities that are immoral or illegal. If this causes a person to stop being in your life, then they are not friends to begin with. True friends only want the best for a friend.
Paul has chosen to have faith in Christ and so to "attain" to the resurrection of the dead. Paul was more concerned with his eternal life than his earthly life and is encouraging his followers to do the same. He is also encouraging us to do the same.
What is there on earth that we can bring with us into eternity? We can't bring money or the latest electronic toy. We can't bring the latest model of our favorite car, or our house or any other thing.
What we can bring is a heart full of love. In Paul's letter to the Corinthians, he talks about the three things that lasts, faith, hope and love and the greatest of these us love. God is love, and the more we love, the more we know God.
Once we die, we no longer need faith, because we will know all we need to know. We will no longer need hope, because we have attained what we had hoped for. What we do bring with us into heaven is love.
The righteousness we desire is born of the love we have for Jesus and is witness by the love we have for others.
