23 And when ye shall come into the land, and shall have planted all manner of trees for food, then ye shall count the fruit thereof as uncircumcised: three years shall it be as uncircumcised unto you: it shall not be eaten of.
Fruitbearing trees are works that bring forth virtues. We circumcise trees when we are suspicious of how weak our first efforts are and do not approve of the first fruits of our work. We call the fruit that grows unclean and do not take it as our food. When the first fruits of good works are praised, it is proper that this fruit should not feed the soul of the worker. Otherwise the praise we receive is plucked, and the fruit of our work is eaten out of season. So one who receives praise from a human mouth for a virtue just undertaken eats the fruit of a tree he has planted before its time. Truth said this through the psalmist: “It is vain for you to rise before dawn; rise up after you have sat down.” To rise before dawn is to rejoice in the night of this present life, before the clear light of eternal rewards appears. We should first sit down and then rise up rightly, because whoever does not willingly humble himself now will not be exalted in the glory to come. Exposition of the Old and New Testament, Leviticus
Fruitbearing trees are works that bring forth virtues. We circumcise trees when we are suspicious of how weak our first efforts are and do not approve of the first fruits of our work. We call the fruit that grows unclean and do not take it as our food. When the first fruits of good works are praised, it is proper that this fruit should not feed the soul of the worker. Otherwise the praise we receive is plucked, and the fruit of our work is eaten out of season. So one who receives praise from a human mouth for a virtue just undertaken eats the fruit of a tree he has planted before its time. Truth said this through the psalmist: “It is vain for you to rise before dawn; rise up after you have sat down.” To rise before dawn is to rejoice in the night of this present life, before the clear light of eternal rewards appears. We should first sit down and then rise up rightly, because whoever does not willingly humble himself now will not be exalted in the glory to come.
Firstfruits: Proeputia, literally, their foreskins; it alludes to circumcision, and signifies that for the first three years the trees were to be as uncircumcised, and their fruit unclean: till in the fourth year their increase was sanctified and given to the Lord, that is, to the priests.
[AD 391] Pacian of Barcelona on Leviticus 19:23