Hebrews 4:6

The rest was not appropriated by those under Moses, nor, in the full sense, by those under Joshua, nor in David's time.

It remaineth that some must enter therein [α π ο λ ε ι π ε τ α ι τ ι ν α ς ε ι σ ε λ θ ε ι ν ε ι ς α υ τ η ν]. jApoleipetai "remains over from past times." The promise has not been appropriated. It must be appropriated in accordance with God's provision. The rest was not provided for nothing. God's provision of a rest implies and involves that some enter into it. But the appropriation is yet in the future. It remains that some enter in. They to whom it was first preached [ο ι π ρ ο τ ε ρ ο ν ε υ α γ γ ε λ ι σ θ ε ν τ ε ς]. Lit. they who were first the subjects of the announcement of the glad tidings. It is desirable to avoid the word preached. See on ver. 2. The Israelites under Moses and Joshua are meant.

Because of unbelief [δ ι α π ε ι θ ε ι α ν]. Rend. for unbelief, disobedience. Comp. ch. Hebrews 3:18. jApeiqeia disobedience is the active manifestation of ajpistia unbelief.