The answer to your question is Satan. He is the one who changed the day by means of another organization. He is the original and ultimate
conspirator.
Rev 13:2 And the beast which I saw was like unto a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion: and the
dragon gave him his power, and his seat, and great authority.
Rev 13:5 And there was given unto him a mouth speaking great things and blasphemies; and power was given unto him to continue forty and two months.
Dan_7:25 And he shall speak great words against the most High, and shall wear out the saints of the most High, and think to change times and laws:
and they shall be given into his hand until a time and times and the dividing of time.
Who Made Sunday Holy?
“Perhaps the boldest thing, the most revolutionary change the Church ever did, happened in the first century. The holy day, the Sabbath, was
changed from Saturday to Sunday. ‘The day of the Lord' was chosen, not from any direction noted in the Scriptures, but from the (Catholic)
Church's sense of its own power…People who think that the Scriptures should be the sole authority, should logically become 7th Day Adventists, and
keep Saturday holy.” — St. Catherine Church Sentinel, Algonac, Michigan, May 21, 1995.
“Question - Which is the Sabbath day?
“Answer - Saturday is the Sabbath day.
“Question - Why do we observe Sunday instead of Saturday?
“Answer - We observe Sunday instead of Saturday because the Catholic Church, in the Council of Laodicea (A.D. 364), transferred the solemnity from
Saturday to Sunday.” — Peter Geiermann, C.S.S.R., The Convert's Catechism of Catholic Doctrine, p. 50, 3rd edition, 1957.
Who Do We Reverence by Keeping Sunday Holy?
“It was the Catholic church which…has transferred this rest to Sunday in remembrance of the resurrection of our Lord. Therefore the observance
of Sunday by the Protestants is an homage they pay, in spite of themselves, to the authority of the (Catholic) church.” — Monsignor Louis Segur,
Plain Talk About the Protestantism of Today, p. 213.
Info came from
here
For more in-depth info on the Sabbath, please
go here
As far as the law being done away with, I recommend checking out these short videos with your bible in hand. They are extremely helpful.
Part 1
Part 2
There is much more that could be said on the topic, but I will leave you with this for now. Bless you all.