There came a man of God to Eli, and said to him, Thus says Yahweh, Did I reveal myself to the house of your father, when they were in Egypt [in bondage] to Pharaoh's house?
"I revealed myself to the house of your father when they were in Egypt." In fact, God revealed himself to all Israel while they were still slaves in Egypt under Pharaoh, but this does not say that he chose Aaron and the Levites at that time, because those choices occurred after the revelation at Sinai.