George Eldon Ladd on Christ's return

From Between Two Worlds:

When Will Christ Return?

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.
—Matthew 24:14

New Testament scholar George Eldon Ladd, writing in the 1950s, comments:

The subject of this chapter is, When will the Kingdom come? I am not setting any dates. I do not know when the end will come.

And yet I do know this: When the Church has finished its task of evangelizing the world, Christ will come again. The Word of God says it.

Why did He not come in A.D. 1oo? Because the Church had not evangelized the world.
Why did He not return in a.d. 1000? Because the Church had not finished its task of world-wide evangelization.

Is He coming soon? He is—if we, God’s people, are obedient to the command of the Lord to take the Gospel into all the world.

. . .  “How are we to know when the mission is completed? How close are we to the accomplishment of the task? Which countries have been evangelized and which have not? How close are we to the end? Does this not lead to date-setting?”

I answer, I do not know. God alone knows the definition of terms. I cannot precisely define who “all the nations” are. Only God knows exactly the meaning of “evangelize.” He alone, who has told us that this Gospel of the Kingdom shall be preached in the whole world for a testimony unto all the nations, will know when that objective has been accomplished.

But I do not need to know. I know only one thing: Christ has not yet returned; therefore the task is not yet done. When it is done, Christ will come. Our responsibility is not to insist on defining the terms of our task; our responsibility is to complete it. So long as Christ does not return, our work is undone. Let us get busy and complete our mission.

. . .  Here is the motive of our mission: the final victory awaits the completion of our task. “And then the end will come.” There is no other verse in the Word of God which says, “And then the end will come.”

When is Christ coming again? When the Church has finished its task.

When will This Age end? When the world has been evangelized.

“What will be the sign of your coming and of the close of the age?” (Matt. 24: 3). “This gospel of the kingdom will be preached throughout the whole world as a testimony to all nations; and then, and then, the end will come.” When? Then; when the Church has fulfilled its divinely appointed mission.

Do you love the Lord’s appearing? Then you will bend every effort to take the Gospel into all the world. It troubles me in the light of the clear teaching of God’s Word, in the light of our Lord’s explicit definition of our task in the Great Commission (Matt. 28: 18-20) that we take it so lightly. “All authority in heaven and on earth has been given to me.” This is the Good News of the Kingdom. . . .  All authority is His. “Go ye therefore.” Wherefore? Because all authority, all power is His, and because He is waiting until we have finished our task. His is the Kingdom; He reigns in heaven, and He manifests His reign on earth in and through His Church. When we have accomplished our mission, He will return and establish His Kingdom in glory. To us it is given not only to wait for but also to hasten the coming of the day of God (II Pet. 3:12). This is the mission of the Gospel of the Kingdom, and this is our mission.

George Eldon Ladd, The Gospel of the Kingdom: Scriptural Studies in the Kingdom of God (Grand Rapids, MI: Eerdmans, 1959), ch. 9, “When Will the Kingdom Come?”