Genesis 47:5

5.And Pharaoh spake unto Joseph. It is to be ascribed to the favor of God that Pharaoh was not offended when they desired that a separate dwelling-place might be granted to them; for we know that nothing is more indignantly borne by kings, than that their favors should be rejected. Pharaoh offers them a perpetual home, but they rather wish to depart from him. Should any one ascribe this to modesty, on the ground that it would have been proud to ask for the right of citizenship, in order that they might enjoy the same privilege as natives; the suggestion is indeed plausible. It is, however, fallacious, for in asking to be admitted as guests and strangers, they took timely precaution that Pharaoh should not hold them bound in the chains of servitude. The passage of Sophocles is known: —

gt;rannon ejmporeu gt;etai,
Kei gt;nou ojti lt; dou gt;lov, kan ejleu gt;qerov mo gt;lh| (184)

">Who refuge seeks within a tyrant’s door,
When once he enters there, is free no more.
Langhorne’s Plutarch

It was therefore of importance to the sons of Jacob to declare, in limine , on what condition they wished to live in Egypt. And so much the more inexcusable was the cruelty exercised towards them, when, in violation of this compact, they were most severely oppressed, and were denied that opportunity of departure, for which they had stipulated. Isaiah indeed says that the king of Egypt had some pretext for his conduct, because the sons of Jacob had voluntarily placed themselves under his authority, (Isaiah 52:4;) but he is speaking comparatively, in order that he may the more grievously accuse the Assyrians, who had invaded the posterity of Jacob, when they were quiet in their own country, and expelled them thence by unjust violence. Therefore the law of hospitality was wickedly violated when the Israelites were oppressed as slaves, and when the return into their own country, for which they had silently covenanted, was denied them; though they had professed that they had come thither as guests; for fidelity and humanity ought to have been exercised towards them, by the king, when once they were received under his protection. It appears, therefore, that the children of Israel so guarded themselves, as in the presence of God, that they had just ground of complaint against the Egyptians. But seeing that the pledge given them by the king proved of no advantage to them according to the flesh; let the faithful learn, from their example, to train themselves to patience. For it commonly happens, that he who enters the court of a tyrant, is under the necessity of laying down his liberty at the door.