John Calvin Commentary Genesis 47:15

"And when the money was all spent in the land of Egypt, and in the land of Canaan, all the Egyptians came unto Joseph, and said, Give us bread: for why should we die in thy presence? for [our] money faileth." — Genesis 47:15 (ASV)

And when money failed. Moses does not mean that all the money in Egypt had been brought into the royal treasury, for many of the nobles of the court were free from the effects of the famine. Rather, the simple meaning of the expression is that nearly all of it had been exhausted, so that the common people then had no money to buy grain, and that eventually, extreme necessity drove the Egyptians to the second remedy, which he is about to discuss.

Moreover, although, like people driven to desperation, they might seem to arrogantly rise up against Joseph, yet the context shows that nothing was further from their minds than to terrify by their boldness the man whose compassion they suppliantly implore. Therefore, the question, Why should we die in your presence? has no other meaning than that they felt themselves ruined, unless his clemency should afford them relief.

But it may be asked how the Canaanites supported their lives. There is indeed no doubt that a grievous pestilence, accompanying the famine, would carry off many, unless they received assistance from other regions or were miserably fed on herbs and roots. And perhaps the barrenness there was not so severe that they could not gather half, or a third, of their food from the fields.