Well again Genesis 1:14 says specifically (in Hebrew) that the heavenly bodies are to be used to determine God's "appointed times" which are listed in Leviticus 23 of which the weekly sabbath is one.
And since God created the sabbath HOLY and it's recorded in the bible it's obvious that he would have TOLD his creation about it. In fact Jesus affirmed this later:
Mar 2:27 And He said to them, "The Sabbath was made for man, and not man for the Sabbath.
Mar 2:28 Therefore the Son of Man is also Lord of the Sabbath."
In other words Christ created the sabbath FOR people. He made the sun, moon, etc and cycles of day night so that men could know WHEN his sabbath occurs. He IS the very LORD that created the sabbath therefore he calls himself LORD of the sabbath. It was MADE for man and of course God's creation was told about it.
Adam and Eve knew about it. We saw earlier that Cain and Abel brought a sacrifice on what is very likely a sabbath.
God REVEALS things to his servants. He REVEALED his laws and commandments to Abraham for example:
Gen 26:4 And I will make your descendants multiply as the stars of heaven; I will give to your descendants all these lands; and in your seed all the nations of the earth shall be blessed;
Gen 26:5 because Abraham obeyed My voice and kept My charge, My commandments, My statutes, and My laws."
Now I will grant you that modern Christianity has muddied this issue because they hitched their wagon to a different "day" long ago. But it's a historical fact that the traditional Church did not officially abandon the sabbath of the Lord Jesus Christ until more than 300 years after his death.
It is not obvious. What is obvious is that there is no mention of God discussing it with Adam. Going on, your whole argument in this reply rests on your suppositions. It is manufacturing something out of nothing. You can't earn my respect by creating a myth.
The Jews kept the Sabbath, but after Christ’s resurrection no biblical data suggests that
Christians kept the Sabbath. They instead kept the Lord’s Day, which historically has been
the first day of the week (Sunday). Every day is for worship, not just the Sabbath. Sabbath
keeping may have some good purposes, but it is not an obligation for believers today, nor
is it a sign of apostasy or disloyalty to God not to observe the Sabbath.
Read the article through. Your (mis)use of Scripture is contrary to good interpretation.