One of the purposes of halakhic Midrash was the exegesis of the Bible. In this regard, the halakhic midrash extant for the Book of Exodus comes from the school of R. Ishmael, which is the Mekhilta of Rabbi Ishmael. The word Mekhilta comes from the Aramaic word מכילתא, which means a collection of rules of interpretation, which is what we today would call Biblical Hermeneutics.
In tractate Beshallaḥ, Chapter 1, we read the following in regard to Exodus 13:19:
And Ye Shall Carry Up My Bones Away Hence. I might understand this to mean immediately after his death, but it says: “With you”— when you go up. And whence do we know that they also carried up with them the bones of all the other founders of the tribes? From the expression: “Away hence with you.”
The midrash recognizes that Moses in the Book of Exodus was quoting words from Joseph that were not recorded in the Book of Genesis. Thus when Moses quoted the expression “with you,” the implication was that Joseph was talking to his brothers whose bones would go with the bones of Joseph.
In other words, had the Book of Genesis mentioned the phrase “with you,” the idea in the Book of Genesis would have suggested that the bones of Joseph (and only those of Joseph) move immediately out of Egypt upon his death. The reader of the Book of Genesis could make the logical inference that the Exodus (in the mind of Joseph) was imminent at the time of his death.
Many manuscripts of the Hebrew Bible (to include the Samaritan Pentateuch) and various other translations have edited and included the words “with you” in the Book of Genesis. While this editorial clarification in the book of Genesis brings the quote into perfect alignment with the quote from Moses in the Book of Exodus, the well-intentioned editorial change loses the very fine and nuanced meaning as discovered by the Mekhilta of Rabbi Ishmael.
Reference:
Lauterbach, Jacob Z. (2004). Mekilta de-Rabbi Ishmael (New ed.). Philadelphia: Jewish Publication Society, 123.