וְהֵשִׁ֤יב לֵב־אָבוֹת֙ עַל־בָּנִ֔ים וְלֵ֥ב בָּנִ֖ים עַל־אֲבוֹתָ֑ם פֶּן־אָב֕וֹא וְהִכֵּיתִ֥י אֶת־הָאָ֖רֶץ חֵֽרֶם׃<br><small>[הנה אנכי שלח לכם את אליה הנביא לפני בוא יום יהוה הגדול והנורא]</small>
Rashi
that he may turn the heart of the fathers back to the Holy One, blessed be He.
Rashi
through the children lit., on. He will say to the children affectionately and appeasingly, “Go and speak to your fathers to adopt the ways of the Omnipresent.” So we explain, “and the heart of the children through their fathers.” This I heard in the name of Rabbi Menahem, but our Sages expounded upon it in tractate Eduyoth (8:7), that he will come to make peace in the world.