Hebrews 3:12

But we will unfold these things at a fit opportunity. At present: he of necessity wrote to those for whom he cared so greatly. For while the reason why he was not sent to them is plain, yet he was not forbidden to write. And that they were becoming fainthearted he shows when he says, “Lift up the hands which hang down, and the feeble knees, and make straight paths” and again, “God is not unrighteous to forget your work and love.” For the soul overtaken by many trials, was turned aside even from the faith. Therefore he exhorts them to “Give heed to the things which they have heard, and that there should not be an evil heart of unbelief.” On this account also, in this Epistle, especially, he argues at length concerning faith, and after much [reasoning] shows at the end that to them [of old] also He promised good things in hand, and yet gave nothing.

Moreover, he makes it plain that they had been a long time in the faith and in afflictions, saying, “When for the time ye ought to be teachers,” and, “Lest there be in any of you an evil heart of unbelief,” and ye became “Followers of them who through patience inherit the promises.”

Ver. 12 . “Take heed, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God.” For from hardness unbelief ariseth: and as in bodies, the parts that have become callous and hard do not yield to the hands of the physicians, so also souls that are hardened yield not to the word of God. For it is probable besides that some even disbelieved as though the things which had been done were not true.

[8.] And [he said] “To-day,” that they might never be without hope. “Exhort one another daily,” he says, [“while it is called today,”] that is, even if a man have sinned, as long as it is “To-day,” he has hope: let no man then despair so long as he lives. Above all things indeed, he says, “let there not be an evil heart of unbelief.” ( c. iii. 12 .) But even suppose there should be, let no man despair, but let him recover himself; for as long as we are in this world, the “To-day” is in season. But here he means not unbelief only, but also murmurings: “whose carcasses,” he says, “fell’ in the wilderness.”

5. What good then do I get except the loss of my soul? For this reason I migrate to the hills like a bird. “I am escaped as a bird out of the snare of the fowlers.” I am living, O evil thought, in the desert in which the Lord lived. Here is the oak of Mamre; here is the ladder going up to heaven, and the stronghold of the angels which Jacob saw; here is the wilderness in which the people purified received the law, and so came into the land of promise and saw God. Here is Mount Carmel where Elias sojourned and pleased God. Here is the plain whither Esdras withdrew, and at God’s bidding uttered all the God inspired books. Here is the wilderness in which the blessed John ate locusts and preached repentance to men. Here is the Mount of Olives, whither Christ came and prayed, and taught us to pray. …