Question: As a young child I was taught that Jesus would not return until everyone on earth had heard the Gospel. Is there any truth to this?
Answer: Yes, there is truth to that. See Matthew 24:14, “And this gospel of the kingdom will be proclaimed throughout the whole world as a testimony to all nations, and then the end will come.” Jesus has just talked about all kinds of terrible things that will happen, cataclysmic events that will point to the end of time. (see 24:3-13) The preaching of the Gospel is the most positive event Jesus talks about. The Gospel, which is the good news about Jesus’ death and resurrection, must be preached in all the world–this doesn’t mean that every person will hear the Gospel–rather that every people group will.
I believe this will ultimately be accomplished through the period known as the Great Tribulation. Revelation 7 describes those who have come to Christ from every tongue, tribe and nation. I believe these are those who have come to Christ through the tribulation.
In the meantime, this should greatly motivate us to go and send missionaries to all parts of the world.