It seems that Marcion interpreted the Parable of the Two Trees as typical Gnostic dualism and opposition between two Gods, the Good Alien God and the Evil Creator God. And only as mere earthly reflection of this cosmic dualism we see good people and evil people to act accordingly on the earth.6:43 For there is no good tree that produceth corrupt fruit;
nor corrupt tree that produceth good fruit.
44 For each tree is known by its own fruit.
For of thorns they do not gather figs,
nor of a bramble bush gather they grapes.
45 The good man out of the good treasure of his heart
bringeth forth that which is good;
and the 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.
So Luke is identical with Marcion:
...while Matthew changes the focus:6:43 “No good tree bears bad fruit, nor does a bad tree bear good fruit. 44 Each tree is recognized by its own fruit. People do not pick figs from thornbushes, or grapes from briers. 45 A good man brings good things out of the good stored up in his heart, and an evil man brings evil things out of the evil stored up in his heart. For the mouth speaks what the heart is full of.
In Matthew the cosmic dualism disappears and in its place there is only the opposition between good people and evil people.7:15 “Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves. 16 By their fruit you will recognize them. Do people pick grapes from thornbushes, or figs from thistles? 17 Likewise, every good tree bears good fruit, but a bad tree bears bad fruit. 18 A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus, by their fruit you will recognize them.
And in Mark?
Apart the Parable of the Fig Tree, there is only an allusion to trees:
(Mark 8:22-26)22 They came to Bethsaida, and some people brought a blind man and begged Jesus to touch him. 23 He took the blind man by the hand and led him outside the village. When he had spit on the man’s eyes and put his hands on him, Jesus asked, “Do you see anything?”
24 He looked up and said, “I see people; they look like trees walking around.”
25 Once more Jesus put his hands on the man’s eyes. Then his eyes were opened, his sight was restored, and he saw everything clearly. 26 Jesus sent him home, saying, “Don’t even go into the village.”
Also in Mark, like in Matthew, the trees allegorize (evil or good?) people, but not more two Gods in conflict as per Marcion.
Some has advanced the idea that in the healing of the blind man of Bethsaida, the first vision of the man was the true reality, and only the second vision was newly an ''obscured'' vision.
If wee assume that ''being like trees'' means to be on the side of the Good God or of the Evil God, then what the blind man is ''seeing'' (the first time) is the same cosmic dualism at work: some are of the Alien God while others are of the Creator God.
The reference to ''walking'' alludes to the free choice of the people: on which side are they?
This may be a subtle clue of the marcionite origin of Mark...