John Calvin Commentary Hebrews 6:18

"that by two immutable things, in which it is impossible for God to lie, we may have a strong encouragement, who have fled for refuge to lay hold of the hope set before us:" — Hebrews 6:18 (ASV)

That by two immutable things, and so on. What God says, as well as what he swears, is immutable (Psalms 12:6; Numbers 23:19). It may be very different with men, for their vanity is such that there cannot be much firmness in their word. But the word of God is extolled in various ways; it is pure and without any dross, like gold seven times purified. Even Balaam, though an enemy, was nevertheless constrained to bring this testimony:

“God is not like the sons of men that he should lie, neither like men that he should repent: has he then said, and shall he not do it? Has he spoken, and shall he not make it good?” (Numbers 23:19).

The word of God, then, is a sure truth and in itself authoritative (αὐτόπιστος, self-worthy of trust). But when an oath is added, it is a surplus added to a full measure. We have, then, this strong consolation: that God, who cannot deceive when he speaks, not being content with making a promise, has confirmed it by an oath.

Who have fled for refuge, and so on. By these words he intimates that we do not truly trust in God except when we forsake every other protection, flee for refuge to his sure promise, and feel assured that it is our only safe asylum. Hence, by the word “flee,” our poverty and our need are set forth, for we do not flee to God except when constrained.

But when he adds the hope set before us, he intimates that we do not have far to go to seek the aid we want. For God himself, of his own free will, meets us and, as it were, puts in our hand what we are to hope for; it is set before us.

But as by this truth he designed to encourage the Jews to embrace the Gospel, in which salvation was offered to them, so he also deprived the unbelieving, who rejected the favor presented to them, of every excuse.

And doubtless this might have been more truly said after the promulgation of the Gospel than under the Law: “There is now no reason for you to say, ‘Who shall ascend into heaven? Or, Who shall descend into the deep? Or, Who shall pass over the sea? For nigh is the word, it is in thy mouth and in thy heart’” (Deuteronomy 30:12; Romans 10:6).

But there is a metonymy in the word hope, for the effect is put for the cause; and I understand by it the promise on which our hope leans or relies, for I cannot agree with those who take hope here for the thing hoped for—by no means.

This also must be added: the Apostle does not speak of a naked promise, suspended as it were in the air, but of that which is received by faith. Or, if you prefer a shorter expression, the hope here means the promise apprehended by faith. By the word laying hold, as well as by hope, he denotes firmness.