John 10:16

16 I have other sheep that are not of this sheep pen. I must bring them also. They too will listen to my voice, and there shall be one flock and one shepherd.

Revelation 20:4

….. They came to life and reigned with Christ a thousand years.

For Christ will reign for a thousand years (the millennium reign, the day of Sabbath),

he will call upon and gather all His other “sheep” who are the atheists, the agnostics, the buddhists, the muslims, Hindu, etc and will listen to Jesus’ voice and gather together as 1 flock for their is only 1 True shepherd (Jesus Christ).

Edit: I am not here to insult or discriminate other religions. I am only here to state what the Holy Bible said that, “One day, we will all gather as One and following One True Shepherd (Jesus Christ)”. Also, I don’t know when will this Millennium Reign of Jesus will start because no one knows. 😊