To prove the identity of the promises under the two dispensations, the
Apostle singles out one promise, which may be considered most
significant of the national no less than the religious life of Israel.
The Greek mind was ever on the alert for something new. Its character
was movement. But the ideal of the Old Testament is rest. Christ came
into touch with the people at once when He began His public ministry
with an invitation to the weary and heavy-laden to come unto Him, and
with the promise that He would give them rest. Near the close of His
ministry He explained and fulfilled the promise by giving to His
disciples peace. The object of our author, in the difficult chapter now
under consideration, is to show that the idea most characteristic of the
old covenant finds its true and highest realisation in Christ. After the
manner of St. Paul, who, in more than one passage, teaches that through
the fall of Israel salvation is come unto the Gentiles, the writer of
this Epistle also argues that the promise of rest still remains, because
it was not fulfilled under the Old Testament in consequence of Israel's
unbelief. The word of promise was a gospel[47] to them, as it is to us.
But it did not profit them, because they did not assimilate[48] the
promise by faith. Their history from the beginning consists of continued
renewals of the promise on the part of God and persistent rejections on
the part of Israel, ending in the hardening of their hearts. Every time
the promise is renewed, it is presented in a higher and more spiritual
form. Every rejection inevitably leads to grosser views and more
hopeless unbelief. So entirely false is the fable of the Sibyl! God does
not burn some of the leaves when His promises have been rejected, and
come back with fewer offers at a higher price. His method is to offer
more and better on the same conditions. But it is the nature of unbelief
to cause the heart to wax gross, to blind the spiritual vision, until in
the end the rich, spiritual promises of God and the earthly, dark
unbelief of the sinner stand in extremest contrast.

At first the promise is presented in the negative form of rest from
labour. Even the Creator condescended thus to rest. But what _such_ rest
can be to God it were vain for man to try to conceive. We know that, as
soon as the foundations of the world were laid and the work of creation
was ended, God ceased from this form of activity. But when this negative
rest had