The Targum Pseudo-Jonathan does not let us wonder how Rebekah heard. "The words of Esau her elder son, who thought in his heart to kill Jakob, were shown by the Holy Spirit to Rivekah" (Genesis 27:42).
Ruach ha-kodesh. The Holy Spirit. The same prophetic whisper that spoke to Sarah, to Hagar, to Miriam, to Deborah. It comes to Rebekah now, warning her that her firstborn is plotting murder in his heart.
Rebekah the prophet
The rabbinic tradition numbers Rebekah among the seven female prophets of Israel, alongside Sarah, Miriam, Deborah, Hannah, Abigail, and Esther (Megillah 14a). She has been hearing from Heaven since the womb — when she learned, before the twins were born, that the elder shall serve the younger (Genesis 25:23). Now, at the other end of the story, the Holy Spirit returns to her with the final warning.
Pseudo-Jonathan is underscoring a pattern. Rebekah's life is bracketed by prophecy. The same sensitivity that heard the twin nations wrestling in her womb now hears the older brother plotting in his heart. She has always been the one who could hear what was coming.
The mother's immediate action
Rebekah does not wait. She calls Jacob — her younger son, the Targum specifies — and tells him plainly: Esau thy brother lieth in wait for thee, and plotteth against thee to kill thee. No softening. No explanation. The prophecy has come, and she acts on it within a single verse.
The takeaway: the rabbis teach that prophecy without action is wasted. Rebekah is the model. The Holy Spirit speaks, and she moves. Pseudo-Jonathan's lesson is simple but urgent — when you know what is coming, get your children out of its path.