Do you have some wisdom to share with me about a matter in Genesis? I’m not being flippant, I’m sincerely needing help in understanding this:

Genesis 1:5
“And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.”

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[I recognize that the Jewish custom says that a day begins at sundown (as a result of scripture such as this). That’s not what I’m asking about].

I’m wondering how to harmonize the data in that verse.

It appears that the first “day” (like all the “days” of creation in Genesis 1) were the hours of nighttime, (darkness).

So then, how do we understand “God called the “light” Day”… when each “day” was quantified/identified by the dark hours of the clock (so to speak).

And since the dark hours are a “day,” then when when does “night” occur?

Help me to understand if you can please.