Reference

Deuteronomy 16:4

And there shall be no leavened bread seen with thee in all thy coast seven days; neither shall there any thing of the flesh, which thou sacrificedst the first day at even, remain all night until the morning.
2

Thou shalt therefore sacrifice the passover unto the Lord thy God, of the flock and the herd, in the place which the Lord shall choose to place his name there.

3

Thou shalt eat no leavened bread with it; seven days shalt thou eat unleavened bread therewith, even the bread of affliction; for thou camest forth out of the land of Egypt in haste: that thou mayest remember the day when thou camest forth out of the land of Egypt all the days of thy life.

4

And there shall be no leavened bread seen with thee in all thy coast seven days; neither shall there any thing of the flesh, which thou sacrificedst the first day at even, remain all night until the morning.

5

Thou mayest not sacrifice the passover within any of thy gates, which the Lord thy God giveth thee:

6

But at the place which the Lord thy God shall choose to place his name in, there thou shalt sacrifice the passover at even, at the going down of the sun, at the season that thou camest forth out of Egypt.

Counter-Arguments

The strongest case that this verse does not belong in this theme.

First Day of the Week

The verse mentions "the first day" in the context of a sacrifice, but it does not specify "the first day of the week." The "first day" here refers to the initial day of the seven-day period of unleavened bread, not a specific day of the weekly cycle.

Seventh-Day Sabbath

The verse mentions "seven days" in relation to leavened bread and the duration of a sacrificial offering, but it does not explicitly or implicitly refer to a Sabbath or a specific day of rest.