Athanasius of Alexandria

A thousand years is the time that the temple worship lasted. For from the completion of the temple by Solomon, who built the Lord’s house until it became redundant when Christ died on the cross is a thousand years. This thousand years is compared to a day, or to a watch in the night, because everything appeared to be night before the coming of the Savior. For until the sun of righteousness arose, everyone dwelt in ignorance and confusion.