Whether John Piper ever believed the Gospel, I don’t know. Whether he will believe the Gospel in the future, I don’t know. What I do know is that John Piper (and John MacArthur, Billy Graham, Franklin Graham, Ray Comfort, Kirk Cameron, Alister Begg, R.C. Sproul, historical Martin Luther, the Roman Catholic Church, Reformed churches, Presbyterians, many Lutherans, and many, many others, most churches and most Preachers–actually most churches in the world), preach salvation by human good works, and not by the biblical way of salvation: believe in Jesus, who died on the cross for your sins and rose from the dead on the third day. (John 6:47 and 1st Corinthians 15:1-4). Salvation is free and permanent gift, received through faith in Jesus, without any of our good works. Most churches see Jesus as a cheerleader for people who think they are saving themselves by their own good works.