John Calvin on Genesis 3:4

4. And the serpent said unto the woman Satan now springs more boldly forward; and because he sees a breach open before him, he breaks through in a direct assault, for he is never wont to engage in open war until we voluntarily expose ourselves to him, naked and unarmed. He cautiously approaches us at first with blandishments; but when he has stolen in upon us, he dares to exalt himself petulantly and with proud confidence against God; just as he now seizing upon Eve’s doubt, penetrates further, that he may turn it into a direct negative. It behaves us to be instructed, by much examples, to beware of his snares, and, by making timely resistance, to keep him far from us, that nearer access may not be permitted to him. He now, therefore, does not ask doubtingly, as before, whether or not the command of God, which he opposes, be true, but openly accuses God of falsehood, for he asserts that the word by which death was denounced is false and delusive. Fatal temptation! when while God is threatening us with death, we not only securely sleep, but hold God himself in derision!