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 (tm rba) , "merebrum emortuum" F20:
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.