Having demonstrated that Christ is the tree beside the waters and that the happy man is he who chooses to be like the tree beside the waters, St. Hilary now expands upon this metaphor:
And, pray, in what season? In the season, of course, of which the Apostle speaks: ‘That He might make known unto you also the mystery of His Will, according to His good pleasure which He hath purposed in Himself, in the dispensation of the fulness of time (Eph 1:9).’ This, then, is the dispensation of time, by which is regulated the right moment of receiving, in the case of the recipients, and of giving, in that of the giver; for the giver has choice of the season. But delay in point of time depends upon the fulness of times. For the dispensation of yielding fruit waits upon the fulness of time. Now what, you ask, is this fruit that is to be dispensed? That assuredly of which this same Apostle is speaking when he says: ‘And He will change our vile body, that it may be fashioned like His glorious body (Phil 3:21).’ Thus He will give us those fruits of His which He has already brought to perfection in that man whom He has chosen to Himself who is portrayed under the image of a tree, whose mortality He has utterly done away and has raised him to share in His own immortality.
This man then will be happy like that tree, when at length he stands surrounded by the glory of God, being made like unto the Lord.
In the fulness of time, God will freely give us the fruits of the Cross. By becoming a human being, by dying on the Cross, by rising on the third day and ascending into heaven to sit at the right hand of the Father in glory with His humanity he makes it possible for all of us to share in that humanity — the New Man, the Last Adam, the Resurrected Christ.
Since our human nature is the same human nature that Christ has as He sits in glory next to the Father, our destiny is to share in that glory. The happy man lives in the hope of this fruit, because he chooses it.