John Calvin Commentary Genesis 40:19

"within yet three days shall Pharaoh lift up thy head from off thee, and shall hang thee on a tree; and the birds shall eat thy flesh from off thee." — Genesis 40:19 (ASV)

Pharaoh shall lift up thy head from off thee. This phrase (in the original) is ambiguous without some addition and can be taken in a good or a bad sense, just as we might say, "With regard to anyone," or "With respect to him." Here, the expression "from thee" is added. Yet there seems to be an allusion of this kind, as if Joseph had said, "Pharaoh will lift up your head so that he may take it off."

Now, when Moses relates that what Joseph had predicted happened to both of them, he proves by this sign that Joseph was a true prophet of God, as it is written in Jeremiah (Jeremiah 28:9).

That the prophets sometimes threatened punishments which God abstained from inflicting happened because a condition was attached to such prophecies. But when the Lord speaks definitively through His servants, it is necessary that whatever He predicts must be confirmed by the outcome. Therefore, Moses expressly commends Joseph's confidence in the heavenly oracle.

Regarding what Moses records—that Pharaoh celebrated his birthday with a great feast—we know that this custom has always been common, not only among kings but also among ordinary people. Nor is the custom to be condemned, if only people would keep the right purpose in view: namely, giving thanks to God, by whom they were created and raised, and whom they have found in countless ways to be a beneficent Father.

But such is the depravity of the world that it greatly distorts those things formerly established in integrity by their ancestors into the opposite, corrupt practices. Thus, through corrupt practice, it has become common for nearly everyone to abandon themselves to luxury and unrestrained indulgence on their birthday. In short, they commemorate God as the Author of their life in such a way that it seems their deliberate purpose is to forget Him.