Thank you for the question, “Why did Jesus curse the fig tree in Matthew 21:18–19?”
As I read Matthew 21:18–19 again to refresh my memory of the context and the text, the reason why Jesus cursed the fig tree was to illustrate that the nation of Israel had all the appearances of being a fruitful tree, but it was barren of any fruit at all.
From a distance, the fig tree looks healthy and should be able to produce figs. As Jesus came close to pick a fruit from that tree, he found none at all. The nation of Israel in all their worship and practices appeared to be a healthy tree and should have found some fruit on it.
John the Baptist came preaching a baptism of repentance. There was a call to repentance but that repentance didn’t last long. The people returned to their old ways after his death. Worship was happening in the Temple, but it was for a show. The rich pour their coins to be noticed by others. The Pharisees prayed prayers to God thanking him that he is not like that sinner over there. The rituals were being performed but there was no heart change in their lives. There was no fruit of repentance.
In the preceding verses, Jesus saw what was happening in the Temple. Barter and money exchangers, animals in the Temple court with all the appearances of helping the worshiper to worship God, but in reality it was a money making business. It was not a house of prayer and praise, but a market place. The priest should have rebuke the trading in the Temple court, but instead they condone it. When the children were praising God, the priests wanted Jesus to rebuke the children for shouting, “Hosanna to the Son of David.” for they didn’t recognize Jesus as that person.
In the subsequent passage, the religious leaders questioned Jesus’ authority to teach and do the sign gifts that he performed in the Temple around Jerusalem. They were not truthful with their answer as to baptism of John the Baptist as being from God or from man. They knew the answer but refused to give an honest answer. They had the appearance of being righteous but they were deceptive.
One would think that the religious leaders would have welcome him and to dialogue with him on his teaching and works that he was doing. Was it clear that at least he was a prophet or teacher from God, but here the religious leaders refused to acknowledge that even though the people believed it. The followers of Jesus wanted something from him, not that they believed in him.
SUMMARY: Appearances may look good, but the test is the fruit itself. If it is a tree that is without fruit of repentance, then the appearance is deceptive.
For more perspectives:
https://www.quora.com/Why-did-Jesus-curse-the-fig-tree-in-Matthew-21-18-19