We are to be concerned about "entering His rest" (Heb 4:1). What is God's rest? "In the beginning God created the heavens and the earth" (Ge 1:1). Then "the heavens and the earth were completed and all their hosts" (2:1). "By the seventh day God completed His work which He had done" (:2). The Greek word for "completed" is "kalah" meaning that the endeavor was at an end, finished and accomplished. "His works were finished from the foundation of the world" (Heb 4:3). Also, "He rested on the seventh day from all His work which He had done" (Ge 2:2). When God refers to his rest he calls it "My rest" (Heb 3:11; 4:3,5). The root Greek word is "katapauo" meaning to cause to cease which results in "katapausis" designating a repose or resting. It was not that God was tired and had to recuperate. God "rested on the seventh day" (Ex 20:11) "and sanctified it, because in it He rested from all His work which God had created and made" (Ge 2:3). In one sense it was a "Sabbath rest for the people of God" (Heb 4:9) because it was associated with the seventh day, in Greek a "sabbatismos."
Why is the rest "for the people of God" (Heb 4:9)? When Job wasn't able to answer God he was asked, "'Where were you when I laid the foundation of the earth?'" (Job 38:4). The plan began an eternity ago. "'Of old, You founded the earth, and the heavens are the work of Your hands'" (Ps 102:25). "'You, Lord, in the beginning laid the foundation of the earth'" (Heb 1:10). Jesus was instrumental because "in the beginning was the Word, and the Word was with God, and the Word was God" (Jn 1:1). "Thus declares the Lord who stretches out the heavens, lays the foundation of the earth, and forms the spirit of man within him" (Zec 12:1). Man is part of creation. "God created man in His own image" (Ge 1:27) as God explained "'according to Our likeness'" (:26). "He chose us in Him before the foundation of the world" (Eph 1:4). Jesus said his reply would be "'inherit the kingdom prepared for you from the foundation of the world'" (Mt 25:34). This is based upon the acceptance of the gospel. In the Old Testament there were "those who formerly had good news preached to them" (Heb 4:6). "The Scripture . . . preached the gospel beforehand to Abraham" (Gal 3:8). Paul cited "the gospel which I preached to you" (1Co 15:1) "by which also you are saved, if you hold fast the word" (:2). It is "that Christ died for our sins according to the Scriptures" (:3) "and that He was buried, and that He was raised on the third day" (:4).
Israel's rest was a main implementation of God's plan. "'If you will indeed obey My voice and keep My covenant, then you shall be My own possession among all the peoples, for all the earth is mine'" (Ex 19:5). Then "all the people answered together and said, 'All that the Lord has spoken we will do'" (:8). Next God explained he would "'bring you in to the land'" (:33). God also related, "'I am going to send an angel before you to guard you along the way and to bring you into the place I have prepared'" (:20). Moses explained "'you have not as yet come to the resting place and the inheritance which the Lord your God is giving you'" (Dt 12:9). Furthermore, "'when you cross the Jordan and live in the land which the Lord your God is giving you to inherit, and He gives you rest from all your enemies around you [you will] live in security'" (:10). But they didn't cooperate and God responded, "'Therefore I swore in My anger, truly they shall not enter My rest'" (Ps 95:11). The Hebrew word for rest is "menuehah" meaning a resting place. The promise of their inheritance was to be a place of rest.