How did Adam know he and Eve would still have children after God told them they would die?
Adam knew because God had evidently told him that, despite the death sentence, he and Eve would still have children and become the parents of the human race. When Adam later called Eve the mother of all living, he was taking God at His Word by faith, contrary to the apparent impossibility of offspring from those doomed to die.
Les explains that before they ate, God had said, “The day thou eatest thereof thou shalt surely die,” and they ate. Since you don’t have offspring from someone who dies, Adam still had that warning ringing in his mind. He knew Eve was headed for death, though not how soon. But Les says faith is taking God at His Word, and this is one place he has to suppose: evidently God had told Adam that in spite of their dilemma, he and Eve would be the propagators of the whole human race, with Eve as mother and Adam as father. After the curse was explained, Adam called Eve “the mother of all living.” If God had told him they would have children, that response was faith—he took God at His Word against all improbable odds.