Jesus taught there would be a separation coming between believers and unbelievers in God when He comes back. As the time of the Day of Christ draws near, the separation has already started.
“All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats. And He will set the sheep on His right hand, but the goats on the left.” – Matt. 25:32, 33
“‘Let both grow together until the harvest, and at the time of harvest I will say to the reapers, “First gather together the tares and bind them in bundles to burn them, but gather the wheat into my barn.” ’ ” – Matt. 13:30