Genesis 1:5

God called, &c. God distinguished them from each other by different names, as the Lord of both. The day is thine, the night also is thine. He is the Lord of time, and will be so till day and night shall come to an end, and the stream of time be swallowed up in the ocean of eternity. The evening Including the following night, and the morning, including the succeeding day, were the first natural day, of twenty-four hours. Some, indeed, by evening understand the foregoing day as being then concluded, and by the morning the preceding night: but the Jews, who had the best opportunity of understanding Moses, who here declares the mind of God in this matter, began both their common and sacred days in the evening, see Leviticus 23:32. The darkness of the evening, preceding the light of the morning, sets it off and makes it shine the brighter.