Thanks for the question.
Because Jesus rose from the grave on Sunday, I need you to show me total proof that it was God that gave the command to change the Sabbath from Saturday to Sunday and not the Catholic Church.
Well, I can't do that because historically the Catholic Church did change the Sabbath from Saturday to Sunday.
It's interesting that most, if not all, Christian denominations following this decision that was made solely by the Catholic Church, yet they dissent on other teachings She preaches in obedience to what the Lord told us.
The implication of your question was that you wanted Biblical proof. The Bible is not a Catechism or book of beliefs. The Bible is a liturgical book meant to be used at our worship service, the Catholic Mass. It was written by Catholics, and their ancestors under the inspiration of the Holy Spirit, for Catholics, for use in our worship service.
At the Reformation, the reformers just took Catholic bibles, removed the sections they didn't like and republished it as the Bible.
Although no Catholic should ever use the Bible to prove anything, we can use the Bible to show how Catholic Teachings are supported in the Bible.
Check out my Scripture Passages page if you are interested in this:
Finally, you said you wanted total proof. While the Church does acknowledge that faith and reason compliment each other, inside and outside the Church, She does not reply solely on reason alone which apparently you are doing.
I hope this helps,