Matthew Poole and continuators on Genesis 1:5

5. And God called the Light Day, and the Darkness he called Night: and the Evening and the Morning were the first day .

It is acknowledged by all, that the Evening and the Morning are not here to be understood according to our common usage, but are put by a Synecdoche each of them for one whole part of the natural day. But because it may be doubted which part each of them signifies, some understand by Evening, the foregoing day, and by the Morning, the foregoing night. And so the natural day begins with the Morning or the light, as it did with the antient Chaldeans. Others by Evening understand the first night or darkness which was upon the face of the Earth, ver. 2. which probably continued for the space of about twelve hours, the beginning whereof might fitly be called Evening, and by Morning the succeeding light or day, which may reasonably be supposed to continue the other twelve hours or thereabouts. And this seems the truer opinion. 1. Because the darkness was before the light, as the Evening is put before the Morning, v. 5▪ and 8. and afterwards. 2. Because this best agrees both with the vulgar and with the Scripture use of the terms of Evening and Morning. 3. Because the Jews who had best opportunity of knowing the mind of God in this matter by Moses and other succeeding Prophets, begun both their common and sacred days with the Evening, as is confessed, and may be gathered from Levit. 23. 32.

Did constitute or make up the first Day, Day being taken largely for the natural Day, consisting of 24 hours: These were the parts of the first Day, and the like is to be understood of the succeeding days. Moreover, God who could have made all things at once, was pleased to divide his work into six days, partly to give us occasion more distinctly and seriously to consider Gods works; and principally to lay the Foundation for the weekly Sabbath, as is clearly intimated, Gen. 2. 2, 3. and Exod. 20. 9, 10, 11.

Marginal references: Heb▪ and the Evening was, and the Morning was, &c.