John 16:28

I came forth from the Father, and am come into the world; again, I leave the world, and go to the Father.

In that day, with the coming of the revelation through the Spirit, there will no longer be need to ask the Lord any questions. Though the personal intercourse between them and their Master had terminated, they would have the benefit and the certainty of a direct communion through the work of the Spirit. And solemnly Jesus assures them that their relation to the Father will be of a nature permitting them to go directly to Him with all their desires and needs, for their prayers will all be made in the name of Jesus. Because the atonement of Jesus has effected peace with the Father, has restored the believers to their position as children of God, they have but to refer to Jesus and His work, to appeal to His redemption, to be assured of the hearing of their prayers. The work of the Mediator and Savior had not been completed, and therefore the disciples had not prayed in His name. But now the road to the Father's heart has been opened, and they shall entreat, they shall ask, knowing that they will receive, and thus have also the fulfillment of their joy. The efficacy of prayer depends upon faith in the Savior as the Substitute of mankind, by whom we have free access to the Father. In order to bring this truth home to the disciples still more strongly, the Lord frankly tells them that His teaching has been, to a large extent, in proverbial, parabolic sayings. But the hour is coming, after He will have entered into His glory, when He will speak to them without pictures or difficult figures, through the work of the Spirit. Then He will also teach them, announce to them plainly, what is meant by knowing the Father, by having the right understanding of His love and mercy. At that time prayer in the name of Jesus will be so strong, so efficacious, that there will not even be need of His special intercession for them. This is necessary, as a matter of course, to establish the right relation between God and the believers. See Romans 8:34. But so great is the Father's love which has been evoked by the love of the believers in Christ and by their firm belief that He came into the world to reveal the Father, to be His Ambassador, that the Father will deal directly with His children and will grant their prayers. And this the disciples should once more be assured of: Jesus went forth from the Father and came into the world to carry into effect the plan of salvation for all mankind. And now He leaves the world and goes to the Father, thus signifying that the work which He intended to perform has been done. That fact establishes the relation between God and the believers, and renders all their prayers in the name of Jesus acceptable to Him. Note: Everything that the believers ask of God in the name of Jesus, by faith in His merit, He will give to them. For they pray as the children of God, that have the nature and manner of their Father. It is self-evident, therefore, that they pray only for such things as please the Father, 1 John 5:14. That includes, above all, that they leave both the time and the manner of the hearing to His fatherly wisdom.