Jesus enters Jerusalem as its king. This reception is short-lived since he will be executed in less than a week. The fig tree requires some explanation. Between Jesus cursing the fig tree and Peter seeing it withered, Mark tells of Israel’s place of worship becoming a place to steal from people. The tree had no fruit, so Jesus curses it for being of no value. The clearing of the Temple shows that the nation of Israel no longer has any spiritual fruit, like the tree. Jerusalem was destroyed by the Romans about 40 years later, and for the most part, those who trusted Jesus in the generations to come would be non-Jews.
Jesus judges fruitlessness pretty harshly. Israel spent many years being fruitless, so it’s not like one bad day brings destruction. But doing what God wants and seeing spiritual fruit as a result matters. Fruit could be others coming to Jesus through us or the growth we experience by following Jesus. If you are coasting through life and accomplishing nothing, God is not pleased.