There certainly is a lot of confusion in Christianity, but that's not God's fault. It's source lies elsewhere:
1Co 14:33 For God is not the author of confusion, but of peace, as in all churches of the saints.
But concerning the 7th day sabbath it's pretty clear when it is:
Exo 16:23 And he said unto them, This is that which the LORD hath said, Tomorrow is the rest of the holy sabbath unto the LORD: bake that which ye will bake today, and seethe that ye will seethe; and that which remaineth over lay up for you to be kept until the morning.
Israel was told when the sabbath was. Since then it's been preserved throughout the centuries, mostly by the Jewish religion.
“But concerning the 7th day sabbath it’s pretty clear when it is:”
OMG, you people are funny. I don’t seem to see the word “Sunday” or “Saturday” in that scripture, but to you it is so clear. Maybe that is why NO TWO religions can agree on “what the bible says”. While you are at it, please explain the book of Revelations to me.