Bede the Venerable
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.
Our Lord continues the words which He had begun against the hypocrites, saying, For a good tree bringeth not forth corrupt fruit; i. e. as if He says, If thou wouldest have a true and unfeigned righteousness, what thou settest forth in words make up also in works, for the hypocrite though he pretends to be good is not good, who doeth evil works; and the innocent though he be blamed, is not therefore evil, who doeth good works.