Matthew Poole and continuators on Hebrews 6:18

18 That by two immutable things , in which it was 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 .

Another end of the Mediator's Oath is here added, God's Oath and a Promise spoken to before, which are firm and stedfast to Eternity; Heaven and Earth may pass away, but they cannot.

i. e. To cease to be himself, for essential Truth to become a Lye, is impossible, its utterly inconsistent with his Nature. He is uncapable to deceive, or speak against his Mind, Numb. 23.19. 1 Sam. 15.29. Psalm 89.35. Titus 1.2. and it is as impossible for him to violate his Promise or Oath.

Such as will vanquish all Doubts, Fears, Jelousies, Sorrows, Distractions, putting the Heart into a quiet, peaceful, setled frame, and stablishing it in it, whatsoever Temptations, Trials, or Persecutions it may meet with from without or within to perplex it.

But it is the Heart only of a persevering Believer, not of common Professors, which is so strongly setled and comforted by them; such who fly to take hold of them, having cleared their Right to them, and possessing their Souls of them by Faith, so to hold fast, as who would no more leave, than Ioab would the Horns of the Altar, being a far greater Security than it, or any City of Refuge whatsoever; retreating to, and keeping in this Strong-hold, nothing can interrupt their Comfort, or hurt them, Iob 13.15, 16. Prov. 18, 10. The Hope set before them is that eternal good and blessed State which is reserved in Heaven for Believers, the Object of their Hope set out to their View and Prosecution as a Prize in the Promise, 1 Pet. 1.3, 4. by a Metonymy of the Effect for the Cause, are Hope, and Good hoped for, joyned together for our Pursuit.