"May they all be one, as You, Father, are in Me and I am in You. May they also be one in Us, so the world may believe You sent Me."
The world will believe the Father sent the Son, when all of the elect are gathered. Then, He shall come in clouds of glory.
First, the Lord Jesus is coming back. Many deny this, but they are foolish. People desire sin, so they make up lies and twist scripture. They do not want to be judged, so Satan blinds them with the most ridiculous fables, so they can slumber. He sears their conscience with a hot iron, rather than them repenting. 2 Peter 3:10 "But the Day of the Lord will come like a thief; on that day the heavens will pass away with a loud noise, the elements will burn and be dissolved, and the earth and the works on it will be disclosed."
Secondly, world evangelism promotes the coming of Jesus. As the elect are saved by the ONE TRUE GOSPEL, we hasten the end, which is not only marked by time, but by the ones the Father gave to the Son. People are in the hour glass, and when the gospel has been preached to the ends of the Earth and every elect member reaches conversion, then God's family will be united, and the world will see the successful Savior.
2 Thessalonians 1:10, "in that day when He comes to be glorified by His saints and to be admired by all those who have believed, because our testimony among you was believed."
He'll be glorified as the most necessary, most perfect Savior and Lord. Every eye will see Him, and every tongue will confess the sending of Jesus to the glory of the Father. Every unbeliever will know they missed out.
Thirdly, receive Him now. He sanctifies through the truth of the gospel, and He sanctified Himself, so the gospel would be valid. He offered Himself to God as the highest, best, and most devoted sacrifice. Ephesians 5:2, "And walk in love, as the Messiah also loved us and gave Himself for us, a sacrificial and fragrant offering to God." He gave up His life by the eternal Spirit [Heb 9:14]. He yielded Himself and suffered.
Don't turn down this glorious gift of being one with God's people. You'll see for yourself eventually that Jesus is Lord.
Finally, this day of appearing is what every believer longs for and every sinner dreads. Clear your conscience by serving Him now, not by believing lies!