Is there any Bible authority for Sunday being the first day of the week?

The terms of your question should be inverted; for it is not Sunday that is called the first day of the week, but the first day of the week that is called Sunday. The number was before the name.

Then when the question is inverted, and it is asked what Bible authority we have for calling the first day of the week Sunday, the reply must be that we have none.

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