John Chrysostom

And if, "they could not," is put, instead of, "they would not," do not marvel, for He saith also in another place, "He that is able to receive it, let him receive it." So in many places He is wont to term choice, power... And what saith the Prophet? "If the Ethiopian shall change his skin, or the leopard his spots, this people also shall be able to do good, having learned evil." He saith not that the doing of virtue is impossible to them, but that because they will not, therefore they cannot.

Homilies On The Gospel Of John 68 ↗

Jerome

If an Ethiopian can change his skin, or a leopard its spots, then you can do good, once you have learned evil. They use this testimony against the Church, those who want to assert different natures; and they say that the darkness or diversity of sins is so great that they cannot pass into whiteness and the beauty of one color: not taking into account what follows: And you can do good, once you have learned evil. …

Commentary on Jeremiah ↗

Bede

Also, he showed so much love in his religion that, leaving behind a queen's court, he came from the farthest regions of the world to the Lord's temple. Hence, as a just reward, while he sought the interpretation of something that he was reading, he found Christ, whom he was seeking. Furthermore, as Jerome says, he found the church's font there in the desert, rather than in the golden temple of the synagogue. …

Commentary on Acts 8:27a ↗