God said it was "'the land of Canaan, which I am going to give to the sons of Israel'" (Num 13:2). So Moses sent twelve leaders to "spy out the land" (:2) "at the command of the Lord" (:3). But when they returned they gave out "a bad report" (:32). Then the people asked, "'Why is the Lord bringing us into this land to fall by the sword?'" (14:3). However, two of the spies replied, "'If the Lord is pleased with us, then He will bring us into this land and give it to us'" (:8). Then God asked, "'How long will they not bellieve in Me, despite all the signs?'" (:11). Therefore, God decided they "shall by no means see the land'" (:23). Who did He say this to "but to those who were disobedient?" (Heb 4:18). "They were not able to enter because of unbelief" (:19). The same applies today. "Be diligent to enter that rest, so that no one will fall, through following the same example of disobedience" (Heb 4:11). "Make every effort" (:11 NIV) and "labour therefore to enter" (:11 NKJV).
Today "a promise remains of entering His rest" (Heb 4:1). It is the promise of the eternal rest of salvation which God provides, because "'It is finished'" (Jn 19:30). "The one who has entered His rest has himself also rested from his works, as God did from His" (Heb 4:10). You don't have to fulfill the requirements of laws like Israel did, or earn it by being remunerated through the hard work of a job. You don't have to prove it to others to be successfully judged for your performance. You don't have to satisfy yourself taking credit by accomplishing it all on your own. When you rest from your own work you trust God for his provision, help and guidance. The offer is "'Come to Me all you who are weary [labour(NKJV)] and heavy-laden [burdened(NIV)] and I will give you rest'" (Mt 11:28).
It seems Jesus is talking to people who are overworked and exhausted. But that's what happens when you conform to the world's rules. He's actually advising to "'learn from Me'" (:28) to institute a new approach to "'find rest for your souls'" (:29). We are advised to be "casting all your anxiety on Him, because He cares for you" (1Pe 5:7). Jesus says, "'Take My yoke upon you'" (Mt 11:29) "'for My yoke is easy'" (:30). A yoke is used for hooking up a plow animal. They call workers laborers who do hard, physical labor. But it doesn't mean that Jesus will get you an easier job. A job might be burdensome and demanding but Jesus says "'My burden is light" (:30). He also states he is "'gentle and humble [meek and lowly(NKJV)] in heart'" (:29). If you submit yourself you won't be bothered as much by pressure and "'you will find rest for your souls'" (:29)