What does Matthew 24:31 mean?

Jesus is describing the great and terrible moment of His return to earth. This is commonly called the second coming of Christ (Revelation 19:11–15). This will be a drastic contrast to Jesus' first arrival on earth (Hebrews 9:28). Instead of being born in obscurity, to a young girl, in a small town, in a small nation, the Son of Man (Matthew 9:6; 16:27; 20:18) will return in the sky with power and glory. Every single person alive on earth will be aware of His arrival. The nations will begin to mourn (Matthew 24:29–30).

By that time, the gospel will be proclaimed through the whole world (Matthew 24:14). Now His angels will travel to every corner of the world where people have believed in Jesus.

As He arrives, Jesus will dispatch angels with the same kind of signal used by a military leader. The angels will gather His elect from everywhere on earth. The phrase "four winds" resembles expressions like "the four corners of earth," as a symbolic reference to "everywhere." The four winds represent the four points on the compass. Believers will be found by the angels "under heaven" from one end of the sky to the other. They will each be gathered to Jesus as He returns to the earth.

The elect are true believers: those who submit to Jesus as the Messiah and Savior, who trust Him for the forgiveness of their sins, counting on His righteousness to make them acceptable to God. To be "elect" is to be chosen, and these people are chosen by God to be His children forever.