Gregory the Dialogist

The eleventh hour is that from the coming of the Lord to the end of the world. The labourer in the morning, at the third, sixth, and ninth hours, denotes the ancient Hebrew people, which in its elect from the very beginning of the world, while it zealously and with right faith served the Lord, ceased not to labour in the husbandry of the vineyard. But at the eleventh the Gentiles are called. For they who through so many ages of the world had neglected to labour for their living, were they who had stood the whole day idle. …

Catena Aurea by Aquinas ↗

Thomas Aquinas

But about the eleventh hour he went out. The fourth hiring is set forth; and he does three things. First, he rebukes; secondly, he excuses; thirdly, they are invited. The second is at they say to him: because no man has hired us. The third is at go you also into my vineyard. He says, therefore, but about the eleventh hour he went out. The ninth hour is the time of Christ. Hence, 1 John 2:18 says: little children, it is the last hour. …

Commentary on Matthew ↗