The next day as they were leaving Bethany, Jesus was
hungry. Seeing in the distance a fig tree in leaf, he
went to find out if it had any fruit. When he reached
it, he found nothing but leaves, because it was not
the season for figs. Then he said to the tree, "May no
one ever eat fruit from you again." And his disciples
heard him say it.
These are the two words that explain Jesus cursing the fig tree. Jesus did things that spoke. He often taught by what he did. Jesus wasn't just grouchy when he did this, but did it for a reason and it's recorded to show something. The context helps to interpret this story. Next to this account are the accounts of Jesus cleansing the Temple. The Holy One came to the Temple and made a negative judgment on what was happening there.
Two things are going on with the fig tree. Jesus approaches it with hunger, looking for fruit to eat and finds leaves without fruit. However, it was not the season for fig trees to bear fruit. It was April, but the season for figs is May/June or September.
When fig trees have leaves, it's a sign that they also have fruit and this tree had the leaves with no fruit. So, it seemed that Jesus might have been OK with the tree bearing fruit early, but what made him curse the tree was that it had leaves without fruit. If the tree had not had leaves nor fruit and Jesus cursed it, it would not have made sense, because in April it is not supposed to have fruit. So, it is obvious that what got Jesus angry was that Israel had the "leaves" out, the religious activity, but without fruit; and he used the fig tree as a metaphor.