John Gill Commentary Hebrews 4:5

"and in this [place] again, They shall not enter into my rest." — Hebrews 4:5 (ASV)

And in this place again
In (Psalms 95:11) he speaks again of another rest distinct from that on the seventh day; which, and not the latter, is what believers under the Gospel dispensation enter into:

if they shall enter into my rest :
that is, unbelievers shall not enter into it; as the unbelieving Israelites did not enter into the typical rest, so neither shall any unbeliever enter into the Gospel rest, the antitype of the former.