Nowhere within the New Testament do you find mention of the Sabbath being changed from Saturday to Sunday
Not even the Catholic Church would try to reason from the scriptures as to why they keep Sunday holy instead of Saturday. In fact if they were to do so they would contradict their own Catechism which states that the change from Saturday to Sunday is their mark of authority.
"We observe Sunday instead of Saturday because the Catholic Church transferred the solemity from Saturday to Sunday."
Peter Geiermann, The Convert's Catechism of Catholic Doctrine (1946 ed.), p.50
So why then do 'Protestants' keep sunday, if they are truly Protestant