Acts 7:9

And the patriarchs, moved with jealousy against Joseph, sold him into Egypt: and God was with him, and delivered him out of all his afflictions, and gave him favor and wisdom before Pharaoh king of Egypt; and he made him governor over Egypt and all his house. Now there came a famine over all Egypt and Canaan, and great affliction: and our fathers found no sustenance. But when Jacob heard that there was grain in Egypt, he sent forth our fathers the first time. And at the second time Joseph was made known to his brethren; and Joseph's race became manifest unto Pharaoh.

Jealousy against Joseph ... Stephen doubtless cited this as an example of the Jews' rejection of their heaven-sent deliverer, prefiguring the rejection of the Christ himself; also, by his mention of Joseph's being made known to the brethren at "the second time," there is a hint that the Jews will really learn who Christ is at the Second Advent.