But great as is the blessedness of peace, Paul intimates that the kingdom of God affords a richer banquet. We have three degrees of beatitude set before us, rising like a climax: righteousness is good, peace is better and joy in the Holy Ghost is best of all, the crowning grace which God has to bestow on believers in his adorable Son. It is the link which unites us with God. It is the first installment of heaven paid on earth in advance.
This is more than the joy which is the natural sequence of right doing. The approval of conscience is the lowest degree of the joy of righteousness. If the act be not merely right but beneficent, if we have by sacrifice benefited some person, the joy rises in quality and intensity. Hence the generous deeds of the unregenerate are to them a source of felicity. This arises from the very constitution of human nature. Happiness and virtue are not divergent but parallel lines. We are as moral beings so constituted that joy must follow the exercise of benevolence. This joy is natural. But the joy of the Holy Ghost is supernatural. It is handed down direct from the Giver of all good gifts through the agency of the Holy Spirit. It flows not in the channels of nature, but is a fruit of the Spirit. Paul intends to discriminate between the natural joy of rectitude and this heavenly joy in Christian experience by styling it the joy of the Holy Ghost. It attends his residence in the soul. For there is a mystery next to the three-fold personality in the unity of the divine nature, the two-fold personality of the believer, the human interpenetrated by the divine personality inhabiting it as his temple. This miracle of the fulness of the Spirit was first manifested in Adam in Eden when the breath of God conveyed not merely animal and intellectual life, but spiritual life resulting from the indwelling of the Holy Spirit. Sin dissolved this mysterious union and the heavenly personage withdrew from his polluted sanctuary. From being filled with joy pervading every capacity, Adam became desolate indeed. The supremely blessed became supremely wretched. To be sundered from God, the fountain of bliss, is hell. When sin entered the soul of Adam that deep celestial spring ceased to send up its refreshing waters, and he became the subject of intense thirst. His posterity born in his fallen image share also his tormenting thirst. They all flew from spring to spring of sensual pleasure, but still they thirsted till Jesus stood up in this spiritual Sahara and cried, "If any man thirst, let him come to me and drink." The satisfying nature and the inexhaustible abundance of the water of life are intimated in the fact that out of the believer shall flow, not drops as from a spile, not brooks which dry up "in the summer's heat, but rivers, Amazons and Mississippis of living water. Then John, in a blessed parenthesis, for which I mean to thank him when I shake hands with him in heaven, strips off the imagery and tells us in plain words that Jesus is describing the joy of the Holy Spirit, who was not yet given in Pentecostal fulness. To this fountain Jesus sets a perpetual finger-point in his last words in the Bible, "The Spirit and the bride say, Come . . . and take the water of life freely."
— Jesus Exultant, Chapter 7.