Jesus said you know the tree or the prophet when the fruit comes.  He pointed out a truly good prophet who is working for God can get grapes from dead trees.

The fruits argument can only work if you keep things simple in relation to ethics. I mean that instead of saying that killers are to be executed to please God one will say that killers should be jailed for life. That is better than killing them which would be too much.

Another example, would be sanctioning the relationship of two homosexuals who love one another and make one another happy and who are committed. It complicates things to condemn them. What happens is that if you complicate things there will be too much conflict and disagreement about right and wrong and Jesus’ insistence on the fruits will be made worthless. A man could abuse a child saying he is a prophet and that God commanded it for a good reason so nobody would be able to prove that it was a bad fruit if they believed him. Since the fruits of Christianity have been so unpleasant we can safely say that it has created bad fruit. How would the fruits argument used by Jesus apply to the likes of the Catholic Church shielding paedophile priests and leaving them free to carry on abusing? Using the principle that it has to be kept simple to make sense we see that it would infer that the Catholic Church is a wolf that hopes to devour the lambs of Christ. The argument would be no use if the excuse: “The fruits exist but you cannot see them for we are not living the fruits”, carried any weight. Jesus did not keep his ethics simple so his use of the fruits argument was just a con and a trick. In the gospel of John he says that everyone will know his true disciples by their love for one another. He’s accepting the argument here too. In accepting it he condemned himself as a wolf. The apostles weren’t very worried if he was a fake when they didn’t use the good trees bear good fruits and bad bear bad argument to see what Jesus really was!

The fruits argument is no good. Jesus wouldn't have believed it anyway. He regarded Moses as a Prophet of God despite that blood-drinker being no better than Hitler. That Jesus even used the argument is a bad fruit! All religious manipulators herald their fruits as signs that God has sent them.
To say that you know a person to be good or bad by their fruits is far too strong as well. We all know people who are really good who we misunderstood. We misinterpreted their fruits. At best, you can say, "I believe - not know - this person is good for he does good things."
If Jesus had really produced good fruits,
He would have raised money for a refuge for the lepers.
He would have upbraided the rich more and got money off them for the poor.
He would have spent many nights cleaning the sores of beggars.
He would have been seen taking his dinner out to the little starving child on the street.
He would have told the schools to stop focusing so much on religion and equip children for the harsh world.
He would have said it was a sin for the authorities to let human waste be dumped anywhere.
He would not have been obsessing about God and scripture and religion - he is even worse than a pope.
Like the apparitions of Medjugorje, Jesus is praised for making people more religious and nobody cares that few if any were inspired to accomplish heroic good works such as tending the sick 24/7 and building hospitals.
All we have are stories about Jesus doing healings. The man who gives you his dinner is far better than the man who without any trouble snaps his fingers and makes you well. It costs him nothing. A rich man who gives a little to the poor in fact deserves greater praise!

No decent or thinking person presents such an irrelevant and confused and silly person as Jesus as the centre of spiritual life.