“Most assuredly, I say to you that you will weep and lament, but the world will rejoice; and you will be sorrowful, but your sorrow will be turned into joy. A woman, when she is in labor, has sorrow because her hour has come; but as soon as she has given birth to the child, she no longer remembers the anguish, for joy that a human being has been born into the world. Therefore you now have sorrow; but I will see you again and your heart will rejoice, and your joy no one will take from you.
“And in that day you will ask Me nothing. Most assuredly, I say to you, whatever you ask the Father in My name He will give you. Until now you have asked nothing in My name. Ask, and you will receive, that your joy may be full.” (John 16:20-24)
He says that His holy disciples will increase in wisdom and knowledge when they should be clothed with power from on high (Luke 24:29) according to the Scripture, and with their minds illumined by the torchlight of the Spirit should be able to conceive all wisdom, even though they asked no question of Him Who was no longer present with them in the flesh. The Saviour does not indeed say this because they will have no more need of light from Him, but because when they had received His own Spirit, and had Him indwelling in their hearts, they would have in their minds no lack of every good thing, and would be fulfilled with the most perfect knowledge. And by perfect knowledge we mean that which is correct and incapable of error, and which cannot endure to think or say any evil thing, and which has a right belief concerning the Holy and Consubstantial Trinity.
For if we see now in a mirror darkly, and we know in part (1 Cor 13) still while we wander not astray from the doctrines of the truth but adhere to the spirit of the holy and inspired writings, the knowledge that we have is not imperfect, a knowledge which no man can acquire save by the light of the Holy Spirit given unto him. Hereby he exhorts the disciples to pray for spiritual graces, and at the same time gives them this encouragement – that what they ask they will not fail to obtain; adding the comforting assurance of the word “verily” to His promise that if they will go to the Father’s throne and make any request, they will receive it of Him, He Himself acting as Mediator and leading them into the Father’s Presence.
For this is the meaning of the words in my Name; for we cannot draw near unto God the Father save by the Son alone. For through Him we have obtained access in One Spirit unto the Father (Eph 2:18), according to the Scripture. Therefore also He says: I am the Door: I am the Way: no one comes unto the Father but by Me (John 14:6). For inasmuch as the Son is also God, together with the Father He conveys good gifts to the Saints, and associates Himself with Him in granting us the portion of the blessed. Moreover, the inspired Paul most evidently confirms our belief herein by writing these words: Grace to you and peace from God our Father and the Lord Jesus Christ. And in right of His titles, Mediator, High Priest, and Advocate, He conveys to the Father prayers on our behalf, for He gives us all boldness to address the Father.
In the Name then of Our Saviour Christ we must make our requests, for so will the Father most readily grant them, and will give to those that ask good gifts, that we may take them and rejoice therein. So being fulfilled with spiritual graces, and enriched with the grant of knowledge from Him through the Holy Spirit dwelling in our hearts, we shall gain a very easy triumph over every strange and abominable lust; and thus being active in good works, and attaining to the practice of every virtue with fervent zeal, and strengthened with everything whatsoever that makes for sanctification, we rejoice with exceeding joy at the prospect of the reward that awaits us; and, dismissing the despondency that springs from an evil conscience, we have our hearts enriched with the joy that is in Christ. This did not enter into the life of the men of old time; they never practiced this manner of prayer, for they knew it not. But now is it ordained for us by Christ, at the appropriate season, when the time of the accomplishment of our redemption was fulfilled, and the perfect fruition of all good was gained for us by Him. For just as the Law accomplished nothing, and as righteousness according to the Law was incomplete, so also was the mode of prayer inculcated thereby.
[St. Cyril of Alexandria, Commentary on the Gospel of St. John, Book XI]