We see God's "promise being left us" (Heb 4:1 KJV) since the "promise remains" (:1 NASB). A "sabbath rest remains open for the people of God" (:9) and "it remains for some to enter it" (:6). Christ accomplished it and it is available as a usable provision to appropriate. Just some entering it is specified because only those who have "believed do enter into rest" (:3). It is called an entrance as we "draw near with confidence to the throne of grace" (:16). This restoration is an inward, spiritual relationship composed of an ongoing peaceful communion. It is explained as "the good news of the promise made to the fathers" (Ac 13:32) which "God fulfilled . . . in that He raised up Jesus" (:33). "Through Him forgiveness of sins is proclaimed to you" (:38) and "everyone who believes is freed from all things" (:39).
A logical argument is presented because "rest" is mentioned many times and clauses are connected by words such as "for" (Heb 4:8), "so"(:9) and "therefore"(:10). "For the one who has entered His rest has himself also rested from his works, as God did from His" (:10). It is timely for us since "He again fixes a certain day, 'Today' (:7). It was God "saying through David after so long a time just as has been said before" (:7). The situations at Meribah and Massah had been previously mentioned (Ps 95:8). David prophesied, "'Today, if you hear His voice, do not harden your hearts'" (:7). If it had only applied to Joshua then "He would not have spoken of another day after that" (:8).
The situation is composed of those believing the gospel versus Israel's trust in entering the promised land. They failed to enter because they had no confidence in God's promise which was "not mixed with faith in them that heard it" (Heb 4:2). Mixing is deliberately incorporating ingredients producing an actual substantial result. It is a deliberate decision because it says "let us be diligent to enter that rest, so that no one will fall" (:11). The Greek word "pipto" means to fall or fall down. If you're not careful you'll fall "through following the same example of disobedience" (:11). It says that you'll fall and not just trip over something. Was God not angry "with those who sinned, whose bodies fell in the wilderness?" (3:17). Those bodies that fell died. Branches "were broken off for their unbelief" (Ro 11:20) and "to those who fell [it was] severity" (:22). However, "if they do not continue in their unbelief, [they] will be grafted in" (:23). Our insurance is that "we have a great high priest who has passed through the heavens, Jesus the Son of God, therefore let us hold fast our confession" (Heb 4:14).