Charles Ellicott Commentary Genesis 45:8

"So now it was not you that sent me hither, but God: and he hath made me a father to Pharaoh, and lord of all his house, and ruler over all the land of Egypt." — Genesis 45:8 (ASV)

But God. —Hebrew: but the God. The article is rarely found with Elohim in the history of Joseph, but wherever it is added it is a sign of deep feeling on the speaker’s part. (Compare Genesis 48:15.) It was the Elohim, who had been the object of the worship of their race, that had now intervened to save them.

A father. —This was a not uncommon title of the chief minister or vizier of Eastern kings.