Basil of Caesarea

Evening is then the boundary common to day and night; and in the same way morning constitutes the approach of night to day. It was to give day the privileges of seniority that Scripture put the end of the first day before that of the first night, because night follows day: for, before the creation of light, the world was not in night, but in darkness. It is the opposite of day which was called night, and it did not receive its name until after day. Thus were created the evening and the morning. …

The Hexaemeron, Homily 2: The Earth Was Invisible and Unfinished ↗

Ambrose of Milan

The angels, dominions and powers, although they began to exist at some time, were already in existence when the [visible] world was created.

The Six Days of Creation ↗

Bede

And He called the light Day, and the darkness He called Night. This was said for our understanding; for in what language did God call the light Day and the darkness Night; whether in Hebrew, or Greek, or some other language! And so for everything else that He named, it can be asked in what language He named them; but with God, there is pure understanding without noise and diversity of tongues. …

Commentary on Genesis (Hexaemeron) ↗

Hippolytus of Rome

He did not say "night and day," but "one day," with reference to the name of the light. He did not say the "first day; "for if he had said the "first" day, he would also have had to say that the "second" day was made. But it was right to speak not of the "first day," but of "one day," in order that by saying "one," he might show that it returns on its orbit and, while it remains one, makes up the week.

Hippolytus Exegetical Fragments - On Genesis ↗