In faith, etc. If you prefer to omit one of the negatives you may render it thus, "Being weak in faith, he considered not his own body," etc.; but this makes no sense. He indeed shows now more fully what might have hindered, yea, and wholly turned Abraham aside from receiving the promise. A seed from Sarah was promised to him at a time when he was not by nature fit for generating, nor Sarah for conceiving. Whatever he could see as to himself was opposed to the accomplishment of the promise. Hence, that he might yield to the truth of God, he withdrew his mind from those things which presented themselves to his own view, and as it were forgot himself. You are not however to think, that he had no regard whatever to his own body, now dead, since Scripture testifies to the contrary; for he reasoned thus with himself, "Shall a child be born to a man an hundred years old? and shall Sarah, who is ninety, bear a son?" But as he laid aside the consideration of all this, and resigned his own judgment to the Lord, the Apostle says, that he considered not, etc.; and truly it was a greater effort to withdraw his thoughts from what of itself met his eyes, than if such a thing came into his mind. And that the body of Abraham was become through age incapable of generating, at the time he received the Lord's blessing, is quite evident from this passage, and also from Genesis 17 and 18, so that the opinion of Augustine is by no means to be admitted, who says somewhere, that the impediment was in Sarah alone. Nor ought the absurdity of the objection to influence us, by which he was induced to have recourse to this solution; for he thought it inconsistent to suppose that Abraham in his hundredth year was incapable of generating, as he had afterwards many children. But by this very thing God rendered his power more visible, inasmuch as he, who was before like a dry and barren tree, was so invigorated by the celestial blessing, that he not only begot Isaac, but, as though he was restored to the vigor of age, he had afterwards strength to beget others. But some one may object and say, that it is not beyond the course of nature that a man should beget children at that age. Though I allow that such a thing is not a prodigy, it is yet very little short of a miracle. And then, think with how many toils, sorrows, wanderings, distresses, had that holy man been exercised all his life; and it must be confessed, that he was no more debilitated by age, than worn out and exhausted by toils. And lastly, his body is not called barren simply but comparatively; for it was not probable that he, who was unfit for begetting in the flower and vigor of age, should begin only now when nature had decayed. The expression, being not weak in faith, take in this sense -- that he vacillated not, nor fluctuated, as we usually do under difficult circumstances. There is indeed a twofold weakness of faith -- one is that which, by succumbing to trying adversities, occasions a falling away from the supporting power of God -- the other arises from imperfection, but does not extinguish faith itself: for the mind is never so illuminated, but that many relics of ignorance remain; the heart is never so strengthened, but that much doubting cleaves to it. Hence with these vices of the flesh, ignorance and doubt, the faithful have a continual conflict, and in this conflict their faith is often dreadfully shaken and distressed, but at length it comes forth victorious; so that they may be said to be strong even in weakness.

And being not weak in faith - That is, having strong faith.
He considered not - He did not regard the fact that his body was now dead, as any obstacle to the fulfillment of the promise. He did not suffer that fact to influence him, or to produce any doubt about the fulfillment. Faith looks to the strength of God, not to second causes, or to difficulties that may appear formidable to man.
Now dead - Aged; dead as to the purpose under consideration; compare Hebrews 11:12, "As good as dead." That is, he was now at an age when it was highly improbable that he would have any children; compare Genesis 17:17.
Deadness - Hebrews 11:11, "When she was past age;" compare Genesis 18:11.

He considered not his own body now dead - He showed at once the correctness and energy of his faith: God cannot lie; Abraham can believe. It is true that, according to the course of nature, he and Sarah are so old that they cannot have children; but God is almighty, and can do whatsoever he will, and will fulfill his promise. This was certainly a wonderful degree of faith; as the promise stated that it was in his posterity that all the nations of the earth were to be blessed; that he had, as yet, no child by Sarah; that he was 100 years old; that Sarah was 90; and that, added to the utter improbability of her bearing at that age, she had ever been barren before. All these were so many reasons why he should not credit the promise; yet he believed; therefore it might be well said, Romans 4:20, that he staggered not at the promise, though every thing was unnatural and improbable; but he was strong in faith, and, by this almost inimitable confidence, gave glory to God. It was to God's honor that his servant put such unlimited confidence in him; and he put this confidence in him on the rational ground that God was fully able to perform what he had promised.

And being (p) not weak in faith, he considered not his own body now (q) dead, when he was about an hundred years old, neither yet the deadness of Sara's womb:
(p) Very strong and steadfast.
(q) Void of strength, and unfit to have children.

And being not weak in faith,.... Abraham was not weak in the exercise of his faith, on the promise of God; nor was his faith weakened about the accomplishment of it, neither by the length of time after the promise was made, nor by the seeming insuperable difficulties of nature which attended it; for
he considered not his own body now dead. The Alexandrian copy reads without the negative, "he considered his own body now dead", and so the Syriac version: which makes his faith the greater, that though he did consider his case, yet his faith was not weakened: the phrase, "his body now dead", is an "euphemism" of the "merebrum virile", which by the Jews, when unfit for generation, is called , "merebrum emortuum" (t):
when he was about an hundred years old; not being quite an hundred years of age, wanting a year or thereabout:
neither yet the deadness of Sarah's womb; how unfit she was to conceive and bear children: now though he might consider these things in his mind, yet they did not dwell upon his mind, nor he upon them; at least he did not consider them, so as to distrust the divine promise.
(t) T. Bab. Yebamot, fol. 55. 2. & Gloss. in ib. Sanhedrin, fol. 55. 1. & Gloss in ib. Shebuot, fol. 18. 1.

he considered not, &c.--paid no attention to those physical obstacles, both in himself and in Sarah, which might seem to render the fulfilment hopeless.