I received a question from a reader asking if "the rest of the Lord" in Hebrews 4 is the same as the Sabbath rest (presumably in Genesis 2:1-3).
The short answer is the same word is used in Greek in both cases, though Genesis uses the verb form and Hebrews uses the noun.
There is a long answer that is more involved and complicated, uses Hebrew and comes to the opposite conclusion, but given that today is a day of rest I will not go into it.