That made no sense to me if we are observing the letter of the law vs the spirit of the law...
That argument always seemed off to me, just because we have no problem with the letter of each of there other 9 ten commandments. Just the 'spirit' of the fourth?
Doing good on the Sabbath was never the issue. The Pharisees made it a burden. It's not and was never intended to be such.
That's not what scripture says though, we are changing the bible if we say 'it doesnt matter which day'. The commandment is to observe the seventh day. Not the first. Scripture is very clear which is the Sabbath.