BD, The only way that I see Mark 2:27-28 "And He said to them, ‘The Sabbath was made for man, and not man for the Sabbath. Therefore the Son of Man is also Lord of the Sabbath,'" being understood to mean that the Sabbath commandment is no longer binding is to presuppose that the Ten Commandments are no longer applicable, or valid. Anyone that assumes that the Ten Commandments are still binding wouldn't reach the conclusion that this undid the Sabbath.
As for what is "ok" to do on Sabbath, a group of friends and I studied this very carefully and only came to the conclusion that the Holy Spirit has to convict individuals. My reason for generally avoiding the technical trails on Sabbath has nothing to do with physical rest, but if my full focus is on the technical aspects of wheeling how can I really enjoy nature, family and time with God? There are translations that say," thou shalt no do thy own work," which makes it easier to understand for me. God wants us to set a day aside from our normal activities to spent time resting and growing in our relationship with Him, this process is different for everyone. An office worker may need to go for a hike, for example, when a construction worker may prefer sitting on the couch. I don't work on Sabbath, but I'm open to phone calls if I have needed information for others to be productive. How can my Sabbath be seen as a blessing by others if it constantly puts them in a bind? My wife is a PA and does work on Sabbath on a rotational basis. Admittedly, I sometimes wonder where the line is between helping people and "working" is and again it is an individual conviction. If a co-worker was planning to work on Saturday for something important and came down sick at the last minute, I suspect I would be willing to fill in.
As far as tithing, I can assure you that it is a blessing. There are even financial advisors that will recommend an 80/10/10 plan (10% Savings & 10% Charity) because they know it changes people to donate to a cause that benefits something. I personally give both tithes (God asks for 10% of our income) and offering (because I'm thankful). I know many people that double tithe, but I have chosen 13% total because it is approximately 1/7th of my income to match the Sabbath principle. God doesn't promise that we will have everything that we "want" but He does promise to give us what we need.
Done rambling...
