Adam Clarke on John 17:15

That thou shouldest take them out of the world - They must not yet leave the land of Judea: they had not as yet borne their testimony there, concerning Christ crucified and risen again from the dead. To take them away before this work was finished would not answer the gracious design of God. -

1. Christ does not desire that his faithful apostles should soon die, and be taken to God. No: but that they may live long, labor long, and bring forth much fruit.

2. He does not intimate that they should seclude themselves from the world by going to the desert, or to the cloisters; but that they should continue in and among the world, that they may have the opportunity of recommending the salvation of God.

3. Christ only prays that while they are in the world, employed in the work of the ministry, they may be preserved from the influence, του πονηρου, of the evil one, the devil, who had lately entered into Judas, Joh 13:27, and who would endeavor to enter into them, ruin their souls, and destroy their work. A devil without can do no harm; but a devil within ruins all.