John 14:20 - Coke's Commentary on the Holy Bible

At that day ye shall know, &c.— The words rendered and I have a peculiar elegance, which cannot be easily understood without adding the word so in the translation; accordingly the verse would run thus: At that day ye shall know, that as I am in the Father, and you in me, so also I am in you. The verse consists of two parts, as the effects of Christ's resurrection. First, they shall know that Christ is in his Father, that he has eternally dwelt in the Father—that he is one with him by the completest union of essence and councils. Secondly, they shall know that Christ continues in them, communicates his power to them, and has not forsaken them, as by his death they might suspect: they would be convinced to the contrary by his resurrection, by his abiding and conversing with them for forty days after, by his going to heaven to prepare a place for them, by his sending his Spirit to them, and by his indwelling presence, to administer every degree of comfort, light, and power, which would be requisite to render their afflictions supportable, their own souls holy and happy, and their ministry successful. After his resurrection and mission of the Holy Spirit, the disciples could no longer doubt that Christ came from the Father, and dwelt eternally with him; and of course they must have possessed the clearest conviction of that most perfect intercourse which eternally and constantly subsisted between him and his Father: and when they saw the success of their ministry, the Spirit himself bearing them witness by signs and wonders, and enabling them to undertake the arduous, the glorious task, by the gift of tongues, they could not question their apostolic call, nor could they doubt whether Christ was present to them in his divinity, and co-operating with them by his Spirit and power. Thus were they experimentally taught to understand somewhat of that union which is between the Father and the Son, and likewise between Him and the church, or society of Christian believe