Only four times in scripture are we told, ‘be he holy for I am holy…’. Twice in Leviticus 11:44-45 directly connected with food, and once in this portion, directly connected with Sabbath. This is confirmed in Exodus 31:12-17 where Yehovah tells us the seventh day Shabbat is a sign that He sanctifies us.
Don’t shoot the messenger. Rather, ask yourself who changed the day since Scripture NEVER records a change….