Hebrews 4:5

And in this place again, They shall not enter into my rest.

This quotation, as in Hebrews 4:3, is again from Psalms 95:11, serving the purpose, alongside of the quotation from Genesis 2:2, of identifying the rest spoken of here as that of God himself, following the six days of creation, and to which heavenly rest God has always invited people to come and share. To make this place any kind of an argument for people's keeping the sabbath day is to miss the entire argument of the epistle in this portion. The argument is that a rest remains BECAUSE IT WAS NOT ENTERED by the Hebrews! Therefore, it was not entering Canaan nor keeping the sabbath day, for they did that. Thus, the marvelous rest referred to here can be neither of those things but must be understood as a reference back to the rest of God himself which is still in progress, a rest the Jews could have entered but did not, and likewise a rest that many now have the right to enter but may come short of it; hence the warning.