The Interpreter's Bible

regarding Exodus 11:12

In stories of this kind the hero as a rule accidentally discovers the secret of his birth and lineage. This incident may have been lost in editing the various stories which are woven into the Bible narrative. We are left to wonder how Moses learned that he was a Hebrew and not a genuine Egyptian prince. We are inclined to speculate, on the basis of other such stories, about a necklace left around his neck by his mother, or the little garment in which he was found by the princess in the river, preserved throughout the years in the palace, or a chance meeting with his sister, or personal appearance different from other Egyptians. Whatever it was that raised his suspicions that he was not Egyptian, the phrase 'he went out unto his brethren' indicates that he had come to know the secret of his birth. Such a discovery is a test of character..."