The promise of Rest

What is the significance of the seventh day in the Genesis creation saga? This follows up on my previous post about the significance of God resting on the seventh day the commandment to keep the Sabbath. I am reading through Exodus and today I got to chapter 31. I found it noteworthy that the last thing the LORD said to Moses before he gave him the two tablets:

¹⁵ Six days shall work be done, but the seventh day is a Sabbath of solemn rest, holy to the LORD. Whoever does any work on the Sabbath day shall be put to death. ¹⁶Therefore the people of Israel shall keep the Sabbath, observing the Sabbath throughout their generations, as a covenant forever. ¹⁷ It is a sign forever between me and the people of Israel that in six days the LORD made heaven and earth, and on the seventh day he rested and was refreshed.

Again the creation account is linked to the covenant, to the Sabbath rest, and to life and death.