Possible Duplicate:
Why did Avraham take gifts from Pharaoh, but not the King of Sodom?
After Avram saved Lot and the people of Sodom from the 4 kings, the king of Sodom offered him the possessions or spoils for himself in exchange for freeing the people....to which Avram replied:
כג. אִם מִחוּט וְעַד שְׂרוֹךְ נַעַל וְאִם אֶקַּח מִכָּל אֲשֶׁר לָךְ וְלֹא תֹאמַר אֲנִי הֶעֱשַׁרְתִּי אֶת אַבְרָם
Neither from a thread to a shoe strap, nor will I take from whatever is yours, that you should not say, 'I have made Abram wealthy.'
on the other hand, Avram did accept presents from Pharaoh (Bereshis 12:16)
And he benefited Abram for her sake, and he had flocks and cattle and he donkeys and men servants and maid servants, and she donkeys and camels.
so why wasn't Avram worried that Pharaoh would say 'I have made Abram wealthy'?