Ambrose of Milan, on Gen 15:18

“That day God made a covenant with Abram, saying: To thy seed will I give this land, from the river of Egypt even to the great river Euphrates.”

“Foreign peoples are given to Abraham as though for education and so that the most scrupulous mind of the just person might cut away their vices and correct their errors. But what is most evident here is rather the mystery of the church. Through its apostles, "who are Israelites, to whom belong the patriarchs," and from whose patriarchs "Christ was born according to the flesh" under the law, the church was to be constituted from the gathering of pagan peoples who would believe. And it is not by accident that these are indicated by the number ten but rather to show that these, at first unbelievers, when they had completed the measure of impiety, would certainly obtain the crown of faith.”

Imported from an open dataset — not yet checked against the printed edition.