Having established that Christ cannot be the one who finds happiness by meditating upon something He already has (His Law), St. Hilary goes on to show further evidence that Christ is neither the speaker nor the subject of Psalm 1:
But how can the sentence, and he shall be like a tree planted by the rills of water,—wherein growth in happiness is set forth in a figure—be possibly applied to His Person, and a tree be said to be more happy than the Son of God, and the cause of His happiness, which would be the case if an analogy were established between Him and it in respect of growth towards happiness? Again, since according to Wisdom and the Apostle, He is both before the ages and before times eternal, and is the First-born of every creature; and since in Him and through Him all things were created, how can He be happy by becoming like objects created by Himself? For neither does the power of the Creator need for its exaltation comparison with any creature, nor does the immemorial age of the First-born allow of a comparison involving unsuitable conditions of time, as would be the case if He were compared to a tree. For that which shall be at some point of future time cannot be looked upon as having either previously existed or as now existing anywhere. But whatsoever already is does not need any extension of time to begin existence, because it already possesses continuous existence from the date of its beginning up till the present.
St. Hilary is speaking here of the dogmatic understanding of Christ as God. We hear this description of God during the Anaphora of St. John Chrysostom during almost every Divine Liturgy throughout the year:
It is proper and right to sing to You, bless You, praise You, thank You and worship You in all places of Your dominion; for You are God ineffable, beyond comprehension, invisible, beyond understanding, existing forever and always the same.
This is why, when Christ (as it says in Psalm 8:5, “For you have made him a little lower than the angels”), humiliated Himself to take on our humanity, He did so with the express purpose of suffering, going to the cross and dying. Note Matthew 27:46, where Christ says from the Cross, “My God, my God, why have you forsaken me?” This is the first line of Psalm 22, which is a prophecy of Christ’s crucifixion:
1 My God, My God, why have You forsaken Me? Why are You so far from helping Me, And from the words of My groaning?
2 O My God, I cry in the daytime, but You do not hear; And in the night season, and am not silent.
3 But You are holy, Enthroned in the praises of Israel.
4 Our fathers trusted in You; They trusted, and You delivered them.
5 They cried to You, and were delivered; They trusted in You, and were not ashamed.
6 But I am a worm, and no man; A reproach of men, and despised by the people.
7 All those who see Me ridicule Me; They shoot out the lip, they shake the head, saying,
8 “He trusted in the Lord, let Him rescue Him; Let Him deliver Him, since He delights in Him!”
9 But You are He who took Me out of the womb; You made Me trust while on My mother’s breasts.
10 I was cast upon You from birth. From My mother’s womb You have been My God.
11 Be not far from Me, For trouble is near; For there is none to help.
12 Many bulls have surrounded Me; Strong bulls of Bashan have encircled Me.
13 They gape at Me with their mouths, Like a raging and roaring lion.
14 I am poured out like water, And all My bones are out of joint; My heart is like wax; It has melted within Me.
15 My strength is dried up like a potsherd, And My tongue clings to My jaws; You have brought Me to the dust of death.
16 For dogs have surrounded Me; The congregation of the wicked has enclosed Me. They pierced My hands and My feet;
17 I can count all My bones. They look and stare at Me.
18 They divide My garments among them, And for My clothing they cast lots.
19 But You, O Lord, do not be far from Me; O My Strength, hasten to help Me!
20 Deliver Me from the sword, My precious life from the power of the dog.
21 Save Me from the lion’s mouth And from the horns of the wild oxen! You have answered Me.
22 I will declare Your name to My brethren; In the midst of the assembly I will praise You.
23 You who fear the Lord, praise Him! All you descendants of Jacob, glorify Him, And fear Him, all you offspring of Israel!
24 For He has not despised nor abhorred the affliction of the afflicted; Nor has He hidden His face from Him; But when He cried to Him, He heard.
25 My praise shall be of You in the great assembly; I will pay My vows before those who fear Him.
26 The poor shall eat and be satisfied; Those who seek Him will praise the Lord. Let your heart live forever!
27 All the ends of the world Shall remember and turn to the Lord, And all the families of the nations Shall worship before You.
28 For the kingdom is the Lord’s, And He rules over the nations.
29 All the prosperous of the earth Shall eat and worship; All those who go down to the dust Shall bow before Him, Even he who cannot keep himself alive.
30 A posterity shall serve Him. It will be recounted of the Lord to the next generation,
31 They will come and declare His righteousness to a people who will be born, That He has done this.
So, Christ transforms the Tree of the Cross, He is not like the tree. He dies so that we might share in His eternity; He is not like some plant which has a beginning, changes according to the seasons and has an end. As St. Hilary points out, such a comparison makes little sense.