Theophylact of Ohrid

But after the Israelites entered, that is, the chosen ones among them, whom God predestined to His glory (Rom. 8:29–30), such as Peter, the sons of Zebedee, and the rest of the multitude who believed — after that, the grace of God was poured out also upon the Gentiles. For by those found on the "roads" and "lanes" one can understand the Gentiles. The Israelites were inside the city, since they received the law and inherited a civic way of life. …

Commentary on Luke ↗

Gregory the Dialogist

But let us hear what the servant adds after the poor have been brought to the supper: Lord, it is done as you commanded, and still there is room. Many such were gathered from Judea to the Lord's supper, but the multitude that believed from the people of Israel did not fill the place of the heavenly banquet. The throng of Jews has already entered, but there is still room vacant in the kingdom where the multitude of the Gentiles must be received.

Forty Gospel Homilies, Homily 36 ↗

Bede

Lord, it has been done as you commanded, and still there is room Many such were gathered from Judea to the Lord's supper, but the multitude from the Israelite people did not fill the place of the heavenly feast. The crowd of Jews has already entered, but still there is room in the kingdom, where the multitude of the Gentiles ought to be received. Hence, it is also said to the same servant:

On the Gospel of Luke ↗

Bonaventure

Secondly, regarding the compulsion of the negligent, which follows the calling of the humble, he adds: And the servant said: Lord, it has been done as you commanded, and there is still room: because there are not as many humble as there are predestined to life, nor are there as many willing for eternal life as there are predestined by God.

Commentary on Luke, Chapter 14 ↗