"Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath: That by two immutable things, in which it is impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us." (Heb. 6:17-18)
What are these "two immutable [unchanging] things," then? God has taken an oath before those of us who are "heirs of promise," those of us who are beneficiaries of his will. And He swore to this oath by two things that cannot change; two things that God promises He not only will not, but cannot lie about. Of course, we know God can't lie about anything, but He was so adamant that we understand the gravity of this that He inspired the writer of Hebrews to tell us that, even if He wanted to change His mind, He simply could not. But, I repeat, what are these two immutable things?
The first immutable thing, I think, is found in verse 13 of the same chapter, where we read: "For when God made promise to Abraham, because he could swear by no greater, he sware by himself." God may alter his administration, but He cannot change his attributes. He is still just, even when He is the Justifier (Rom.3:26); and He is still the personification of Love, even when He dispenses His wrath (Jno.3:16 & 36). In Malachi 3:6, He tells us, "I am the LORD, I change not."
The second is enunciated plainly for us in verse 17: his counsel. Isaiah 40:8 promises, "[T]he word of our God shall stand for ever." The Word of God cannot change. This is good to know in a day when it seems as though it changes every ten or twenty years! But that is not the case, God tells us. And, just as "the word of the Lord" came to individuals in the Bible, it will come to us, if we are sincerely seeking. In my own case, there is only one Bible through which the word of the Lord comes to me personally: the old KJV 1611. For me, it is—just as it is—the promised, immutable, counsel of God.
In a courtroom, a witness takes an oath to tell the truth; but, if an attorney can prove that he or she is not a credible witness, the oath is meaningless. You and I have no need to worry that the God of Heaven, who has made innumerable promises to us, and has taken a "double oath" in doing so, will ever be discredited. And I, like the writer of Hebrews, find this to be an exceedingly "strong consolation." In fact, all the consolation I need.
"A man is as good as his word"; and, in the case of God, one is as good as the other!