Theophylact of Ohrid

He came at three appointed times: once through Moses, another time through the prophets, and the third time He came personally.

Commentary on Luke ↗

Ambrose of Milan

But our Lord sought, not because He was ignorant that the fig tree had no fruit, but that He might show in a figure that the synagogue ought by this time to have fruit. Lastly, from what follows, He teaches that He Himself came not before the time who came after three years. For so it is said, Then said he to the dresser of the vineyard, Behold, these three years I come seeking fruit on this fig tree, and find none. …

Catena Aurea by Aquinas ↗

Gregory the Dialogist

The lord of the vineyard came to the fig tree a third time, because he sought out the nature of the human race before the law, under the law, and under grace, by waiting, admonishing, and visiting. And he said to the keeper of the vineyard: Behold, these three years I come seeking fruit on this fig tree, and I find none. He came before the law, because through natural understanding he made known what each person should do toward his neighbor by his own example. He came in the law, because he taught by commanding. …

Forty Gospel Homilies, Homily 31 ↗

Bede

Cut it down therefore, why does it even occupy the land? Not by the apostles, but by the Romans the Jewish nation was cut down and cast out from the land of promise. But he says, cut it down, proposing to it the impending downfall with the counsel of repentance. …

On the Gospel of Luke ↗