Augustine of Hippo

The other one, you see, comes along in the evening, and brings what his father ordered, and finds his brother has been blessed instead of himself and is not blessed with a second blessing. Because those two men were two peoples. One blessing signifies the unity of the church. But they are two peoples.… But the two peoples who belong to Jacob are represented in other ways. You see, our Lord Jesus Christ, who had come to Jews and Gentiles, was repudiated by the Jews, who belonged to the elder son. …

Sermon 4.17 ↗

Ambrose of Milan

Afterward, when the blessing had been pronounced, the elder brother arrived. By this it is revealed that the kingdom was predestined to be bestowed on the church rather than on the synagogue but had secretly entered the synagogue so that sin might abound, and, when sin had abounded, that grace might also abound. At the same time, it would be clear that the candidate for the kingdom of heaven must be quick to carry off the blessing and to appropriate the prerogative for which he has been recommended. …

On Jacob and the Blessed Life, Book 2, Chapter 3, Section 10 ↗