"By the seventh day God completed His work which He had done, and He rested on the seventh day from all His work which He had done." - Gen 2:2
"For six days work may be done, but on the seventh day there is a sabbath of complete rest, a holy convocation. You shall not do any work; it is a sabbath to the Lord in all your dwellings" - Lev 23:3
"Therefore, since it remains for some to enter it, and those who formerly had good news preached to them failed to enter because of disobedience, He again fixes a certain day, "Today," saying through David after so long a time just as has been said before, "Today if you hear His voice,Do not harden your hearts." For if Joshua had given them rest, He would not have spoken of another day after that.So there remains a Sabbath rest for the people of God.For the one who has entered His rest has himself also rested from his works, as God did from His. Therefore let us be diligent to enter that rest, so that no one will fall, through following the same example of disobedience." - ( Heb 4: 6-11 )

Rest as a concept - and the hallowing of the seventh day of rest, like the sacrament of marriage, has its origins in Genesis. It doesn't mean getting tired or even pausing to gather energy to work again - rather, if you see the common thread in the quoted texts, it signifies a cessation or end of work.

God finished His work of Creation in 6 days and blessed and sanctified the 7th day as the day on which He was done with His works of creating. Christ accomplished His work of Redemption and sat down at the right hand of God till His enemies be made His footstool (Ps 110:1). The Spirit is at work in the world restraining evil till the time He ceases ( 2 Thess 2:7 ), to usher in the final chapter of human history and reveal the last human emperor.

Rest as a concept is so important to Him that He underlined it in His Law ( by making working on the Sabbath a capital crime ) to His people as a picture, a foreshadow of things to come, through the sacrament of the Sabbath day (Col 2:16-17). It pointed forward to the rest Christ was to bring to the people of God. The book of Hebrews in the text above, unpacks it for us. The Israelites were done with works of wandering when Joshua led them into Canaan, but that was not the only rest God had in mind for them, because the Spirit through David spoke of another day of rest, and through the prophets, spoke of rest from their troubles in the Day of the Lord.

The Pharisees in Jesus' day completely missed the point, reducing the Sabbath day (a day to hallow God by celebrating or looking forward to the day of ultimate rest by temporarily ceasing from our earthly labors for one day) to a set of traditions and rituals to be blindly followed by men. It is still carried out to ridiculous extents even today (not turning on switches!) , by observant Jews, who get the letter, but have completely missed the spirit of the Law, and the bigger picture. God is reminding us, and we are reminding Him (!) every week(!) - of His promise to give us OUR rest from the fight against sin,death and suffering. The Spirit through Paul repeats in Col 2:16-17, we are not to make Sabbath observance a religious trip and argue about which day it is (as some do) but are to observe -A-, -WEEKLY- , Sabbath day with the same respect and reverence by which we partake in Communion, which shows forth His death and resurrection till He comes!

Jesus says it best - "Come to Me, all who are weary and heavy-laden, and I will give you rest." - Matt 11:28 That is the voice we must hear, and obey while we are still alive ( Today! ), so that we may obtain that rest.

If we do not come because of disobedience or unbelief - there is no rest. "But the wicked are like the troubled sea, When it cannot rest, Whose waters cast up mire and dirt. There is no peace, saith my God, to the wicked." ( Is 57: 20-21 )

When Christ said "It is finished" on the cross, He accomplished His mission, and secured for us a spiritual rest. He gave us the peace that passes all understanding. We are to rest in His finished work and look forward to the day when all shall be fulfilled.

"Rest in the Lord, and wait patiently for him: Fret not thyself because of him who prospereth in his way, Because of the man who bringeth wicked devices to pass.Cease from anger, and forsake wrath: Fret not thyself in any wise to do evil.For evildoers shall be cut off:But those that wait upon the Lord, they shall inherit the earth." - Psalm 37

We suggest you read the whole of Psalm 37 - it tells you very clearly how we are to live in the light of our spiritual rest, which the Spirit gives us! One line in particular has its echoes in the admonition of the book of Hebrews to hear His voice....
"Mark the perfect man, and behold the upright:For the end of that man is peace."

Hallelujah!!!