Charles Ellicott Commentary Exodus 31:15

"Six days shall work be done, but on the seventh day is a sabbath of solemn rest, holy to Jehovah: whosoever doeth any work on the sabbath day, he shall surely be put to death." — Exodus 31:15 (ASV)

Six days.—Compare Exodus 20:9.

The sabbath of rest.—Rather, a sabbath of rest, or a complete rest. The repetition (sabbath sabbâthôn) gives an idea of completeness.