Live a life that's worthy of the Gospel.
We are saved by faith, so do we just have to believe to have eternal life? In this video, John Piper points out that joy in God can't be separated from saving faith.
Yes, everything else is worthless when compared with the infinite value of knowing Christ Jesus my Lord. For his sake I have discarded everything else, counting it all as garbage, so that I could gain Christ and become one with him. I no longer count on my own righteousness through obeying the law; rather, I become righteous through faith in Christ. For God’s way of making us right with himself depends on faith.