Psalms 52:8

But do you want me to show you from the Scriptures that trees or wood are given the name of individual virtues, which we mentioned above? I turn to the most wise Solomon as a witness when he said about wisdom, "The tree of life is for all who embrace it." Therefore, if "wisdom is the tree of life," without a doubt, there is another tree of prudence, another of knowledge and another of justice. For logically it is not said that only wisdom, of all the virtues, was worthy to be called "the tree of life" but that the other virtues did not receive names of similar sort. Therefore, "the trees of the field will give their fruit." This is what I believe the blessed David also understood about himself when he said, "But I am as a fruitful olive tree in the house of God." From this he clearly shows that the olive tree designates a just and holy person.

You are being armed not with perishable but with spiritual weapons. The paradise in which you are being planted is the soul's paradise, wherein you will be named with a name you did not have before. You were a catechumen till now, but now you are to be called believer. Henceforth you are transplanted among the olives of that paradise or are being grafted on a good olive tree being taken from a wild olive. You pass from sins to righteousness, from defilements to purity. You are becoming part of the holy Vine. If, then, you abide in the Vine, you grow into a fruitful branch; but if you do not so abide, you will be burned up in the fire. Let us therefore bring forth worthy fruit. For let not that come about, that there should happen to us what happened to the barren fig tree in the Gospel. Let not Jesus come in these days and utter the curse on the fruitless; instead may all of you say, "I am like a green olive tree in the house of God; my trust is in the tender mercy of God, forever and ever"; not a material olive tree but a spiritual and glorious one. It is God who plants and waters, but it is yours to bear fruit; God's to bestow the gift, and yours to receive it and keep it forever. But do not esteem the gift lightly because it is given freely. Rather, receive it reverently and guard it with care.

From what I have said already, we have learned what sort of end the one who is powerful in wickedness will obtain. But as for me, says David, since I have been taught this by the Holy Spirit, I would never be exalted over abundance of wealth, nor over the vanity of mortal life. For "vanity of vanities, all is vanity." But also, as I flee from the path of the one who is powerful in wickedness, I would not sharpen my tongue and my words for the destruction of others, but rather for the benefit of souls and the service of the words of salvation. And in my other actions too, I would become so flourishing and fruitful that my soul would be compared with an ever-flourishing and richly fruitful plant that has been planted in the house of God. For this reason, I say: "But I am like a fruitful olive tree in the house of God"—or, according to Symmachus' translation: "But I am like a flourishing olive tree in the house of God." For I did not turn away at all from the house of God; rather, after being planted inside it, as it were in God's own garden, and while enjoying the streams of the spring in the house of God, I became richly fruitful and ever-flourishing, in accordance with the pattern of the planted olive tree that has been received among the ever-flourishing [plants]. But observe that when David said this, he was not in Jerusalem, which the Jewish people considered to be the house of God—for it had not yet been built; and neither was he in the tabernacle built by Moses, which did still exist at that time among the Jews. For when he was fleeing from Saul, he passed his time among others—and yet he did indeed know that he had been planted in the house of God, since he understood the "house of God" to be the pious way of life. And because he was fruitful—not bearing bitter fruits but sweet fruits full of compassion, he was rightly compared to a fruitful olive tree: the pattern signifying mercy towards one's neighbors and compassion toward all. Therefore, since he was overflowing with this sort of good things, he logically added, "I have put my hope in the mercy of God forever, even forever and ever." Now, he pointed out that the end of the one who is powerful in wickedness is uprooting and destruction. For it was necessary for the root that bears bitter fruit to be †------ off† by the wise farmer of the universe. But David, like a fruitful olive tree in the house…