As for the sabbath:
1. There is no way of accurately counting back the weeks for thousands of years to determine which day is originallly the seventh, and that was never the intention.
2. The original sensibility was that, apart from rest being necessary, to live the life of someone aimed at the afterlife, a complete break from the routines enforced by this temporal life is crucial. That has still being achieved - most people can deviate from work routine on Sunday without the usual pangs of anxiety. To do good on whatever day the Sabbath is, as Jesus indicated, is no transgression of the intention of the Law. He also alluded to this by saying that the sabbath is there for man, not the other way around. There is no better way to rest the soul than to do good.
Living the religious life as described by James (do good to orphans and widows and resist being soiled by this world) is impossible without having one special (holy) day per week.
There is, as usual, no contradiction here except for those who want there to be a contradiction. The free rein on interpretation given with regard to the Word of God is, as I've indicated before, intentional.





