Titus of Bostra
Catena Aurea · Lukasevangelium 6
For a good tree bringeth not forth corrupt fruit; neither doth a corrupt tree bring forth good fruit. For every tree is known by his own fruit. For of thorns men do not gather figs, nor of a bramble bush gather they grapes. A good man out of the good treasure of his heart bringeth forth that which is good; and an evil man out of the evil treasure of his heart bringeth forth that which is evil: for of the abundance of the heart his mouth speaketh.
But take not these words to thyself as an encouragement to idleness, for the tree is moved conformably to its nature, but thou hast the exercise of free will; and every barren tree has been ordained for some good, but thou wert created unto the good work of virtue.