The work week and sabbath as set forth in the mosaic law, is done as a symbol of remembrance for God's creative works. Just like communion is a symbol of Jesus giving his body and blood for us on the cross. It's not an exact representation of the original, it's a symbol. And Genesis chapter 1 is written poetically. It conveys literal truth, but in a way that's easy for anyone to understand. Contrast it with the book of numbers, both written by Moses but in very different styles. Edit: after reading your question again, are you asking about the death penalty? If so, breaking the sabbath was a capitol offense in the theocracy of ancient Israel. No interpretation needed.