Starting with God's rest on the 7th day of creation, the concept of "rest" itself becomes a regular motif in both the Old and New Testaments.
Entering into rest with God is often portrayed as the entire point of life:
Exodus 33:12-14 - Moses said to the Lord, “You have been telling me, ‘Lead
these people,’ but you have not let me know whom you will send with me. You
have said, I know you by name and you have found favor with me.’ If you are
pleased with me, teach me your ways so I may know you and continue to find
favor with you. Remember that this nation is your people.”
The Lord replied, “My Presence will go with you, and I will
give you rest.”
Psalm 62:1-2 - Truly my soul finds rest in God;
my salvation comes from him.
Truly he is my rock and my salvation;
he is my fortress, I will never be shaken.
Jeremiah 6:16 - This is what the Lord says:
“Stand at the crossroads and look;
ask for the ancient paths,
ask where the good way is, and walk in it,
and you will find rest for your souls.
But you said, ‘We will not walk in it.’”
And then remember Jesus' offer in the New Testament?
Matthew 11:28-30 - "Come to me, all you who are weary and burdened, and I will give you rest. Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. For my yoke is easy and my burden is light."
This is not the sort of resting you need a hammock for. You can tell because there is still a yoke involved (meaning there is still work to be done) - but it is Jesus' yoke. This is resting from all the striving and stress of life. This is resting from work, yes, but the efforts of working for God's approval.
We are reminded by Hebrews 4:9-11 that "There remains, then, a Sabbath-rest for the people of God; for anyone who enters God’s rest also rests from their works, just as God did from his. Let us, therefore, make every effort to enter that rest, so that no one will perish by following their example of disobedience."
This puts a different spin on what a Sabbath observance is all about.