The sometimes heard idea that "many now living will never die but live forever in paradise on earth" differs from Paul telling us that all sin and therefore all will die.  Read 1 Corinthians 15:22.   Not only Paul, but Christ and others time and again said the gospel or Good News is the Resurrection Hope, not living forever on earth.  In Genesis, Adam and Eve were told they would never die but could live forever in paradise. (Read Genesis 3)  Not God but a serpent made this false prediction or claim. 

Also, although Ecclesiastes 1:4 says Earth will never end, Christ and the Bible say heaven and Earth will pass away although a new heaven and Earth will come. (Read Matthew 24:35; Luke 21:33, Revelation 21:1)  So precisely as Ecclesiastes says, our planet Earth has come and it will go away even as the different generations of humans do, but yet the Earth will be recreated and in this sense it definitely remains forever.

Paul said there was one true faith and hope. (Ephesians 4:5)  The faith which he spoke of was and still is Christianity in general, although it has like a huge tree had good, average and bad branches.  Although some branches and individual Christians have been like weeds or an unproductive fig tree, happily most have produced some to many good fruits, that is love, joy, peace etc.  In fact Revelation 19:1 says there will be a "great crowd" in heaven. 

Thanks for reading this and for even more understanding please also read and reflect upon John 14:2, 3; 1 Corinthians 15:20, 2 Corinthians 5:1, 2; Galatians 1:8, Philippians 3:20, James 1:17.  The website christianwitnesses.com has information on many other topics of interest that use scriptures explaining and defending traditional Christian beliefs.    You are welcome to make and use copies.