The ONE WORLD COURT SYSTEM IS HERE and focusing now on the middle east because thats where Bible prophecy will be fulfilled in the changes coming about.

Will a law be also established in the land changing God's seventh day into the eight or first day of the week under the system to come?

To God, seven is an important number with meaning.

Why did the Lord God take seven days to make the present world, when surely an omnipotent God could have done so instantly, with a single word?
The answer is so simple that it may astound you.

The Scriptures say that there are seven Spirits of God (Rev. 3:1, 4:5, 5:6).
There are numerous places throughout the Scriptures where God denotes things in "sevens" or multiples of seven.
The Bible also shows us that God uses "sevens" throughout the Scriptures to denote prophetic time

Sevens In Time.
http://www.kjvbible.org/seven_days.html