God communicates through ideas not mere words like a man. Our entire universe was created from the ideas of God. So, the ideas of God surround our physical existence in this universe. Hence, the idea of bearing fruit is known by all humans. We realize if plants don't bear fruit many of us will die. Similarly, if human beings don't "bear fruit" many of us will die.
Now those who don't read Hebrew may not realize that the words for trees and carpenter are the same in Hebrew. Hence, in Hebrew there is a linguistic parallel between trees and men. However, I don't need to know Hebrew to make the philosophical leap that - I should bear fruit for the hungry so they won't die just as the trees bear fruit for me so that I can eat.
Also, it didn't help the Pharisees who could read Hebrew. When Jesus told the Pharisees that they should bear fruit they rejected His message. The Pharisees didn’t grasp the concept that all the trees that God placed in Paradise bore fruit. I hope you got the message – there aren’t any trees in Paradise that don’t bear fruit.
And God said, “Let the earth bring forth herb and grass that sow seed, and fruitful trees that bear fruit, every one in his kind, having their seed in themselves, upon the earth. And it came so to pass.” - Genesis 1:11
May you always be fruitful,
Dr. J. Clontz, Editor of The
Comprehensive New Testament