God doesn't allow it, He requires it. Six days shalt thou labor but on the seventh day ye are to rest and keep it holy. Saying one is keeping all of them holy is treating them all the same. That is not what God commanded. Sure, you are supposed to be good all days of the week, but God wants us to set ONE day aside to worship Him. The day he designated, not the one you pick or your church picks or what the whole world picks. "If you love Me, keep My commandments".
Your bible study is lacking.. You've missed something.. maybe a lot..
"the new covenant, not of the letter but of the Spirit; for the letter kills, but the Spirit gives life."
Now if you're Jewish then you must defer to the Talmud which is what a bunch of Rabbi's think the "letter of the word" really means.. They do a verbal dance around the Spirit of the word, like Shamans..