וַיְצַ֥ו אֶת־הָרִאשׁ֖וֹן לֵאמֹ֑ר כִּ֣י יִֽפְגָּשְׁךָ֞ עֵשָׂ֣ו אָחִ֗י וִשְׁאֵֽלְךָ֙ לֵאמֹ֔ר לְמִי־אַ֙תָּה֙ וְאָ֣נָה תֵלֵ֔ךְ וּלְמִ֖י אֵ֥לֶּה לְפָנֶֽיךָ׃
Und er befahl dem Ersten an: Wenn dir mein Bruder Esau begegnet und dich fragt: Wem gehörst du an, wohin gehst du, und für wen sind diese da vor dir?
Rashi on Genesis
למי אתה means TO WHOM DO YOU BELONG, implying who has sent thee? The Targum should be דמאן את “of whom are you” and not למאן את as some editions have.
Rashbam on Genesis
למי אתה, the word עבד is implied, i.e. Esau would ask: “whose servant are you?”
Or HaChaim on Genesis
ויצו את הראשון לאמור, He instructed the first one (messenger) to say, etc. The apparently superfluous word לאמו was that even if Esau were not to phrase his enquiry in exactly the words Jacob assumed he would, he would no doubt use words to that effect.