Jesus Christ (God Himself manifested on Earth) gave authority to His Apostles.<quoted text>
But Clay, the error you make is that the Fourth Commandment is in God's Holy Law. Immutable and never changeable.
You do keep the Ten Comandments, don't you? Most Christians claim to. at least nine of them. You don't have to be a Jew to keep 9 of them, so why do you have to to keep #4?
Authority that Heaven and all the Angels would recognize as valid.
If you're going to claim yourself a Christian, you need to recognize that the Apostles established Sunday as the Lords day. This is what they commanded. Heaven acknowledge it as valid.(Matthew 16:19)
If you want to undo their authority and invent a 'joint' Judaism/Christian religion then you're acting on your own accord and without the authority to make such decisions.