(Vere, Stein Atle. ©2011. "Shabat for Notsrim". brakha.blogspot.com.)
For the State of Yisrael, the two-day weekend must be Friday-Saturday.
The majority of Yisrelim are Yhudim יהודים (Jews) whose Shabat is on Saturday. The largest minority are Muslmim מֻסְלְמִים (Muslims) whose day of rest is on Friday.
There is also a significant minority of indigenous Notsrim נוֹצְרִים (Christians), whose day of rest is now on Sunday. But Notsrim can be flexible.
Their name derives from a Notsri (Nazarene), an inhabitant of the Yhudi town of Natsrat נָצְרַת (Nazareth).
Yhoshua יְהוֹשֻׁעַ (Historical Jesus) himself is a Yhudi who "unlabors" שבת on Saturday (and also on Yhudi holy days such as Pesakh). Only centuries later at the Council of Nicaea, did the Roman Empire switch the day of rest from biblical Shabat-Saturday to Sunday (also from biblical Pesakh to Easter), literally for "convenience". Notsrim can make any day a day of rest.
To honor Yhoshua, modern Yisreli Notsrim can return to his Yhudi rhythm, and like him rest on Shabat (also on Pesakh).
By contrast, Sunday is Day One. This is a day for new beginnings, not rest. The Notsri worldview has Yhoshua resurrect on Sunday because, on that day, God begins the Six Days of Labor, to create a new creation.
• (Reichman, Libby. ©2011. "This Country Really Needs a Real Weekend". JPost. http://www.jpost.com/Opinion/Op-EdContributors/Article.aspx?id=216889, 2011.)