וַתֵּ֤רֶד בַּת־פַּרְעֹה֙ לִרְחֹ֣ץ עַל־הַיְאֹ֔ר וְנַעֲרֹתֶ֥יהָ הֹלְכֹ֖ת עַל־יַ֣ד הַיְאֹ֑ר וַתֵּ֤רֶא אֶת־הַתֵּבָה֙ בְּת֣וֹךְ הַסּ֔וּף וַתִּשְׁלַ֥ח אֶת־אֲמָתָ֖הּ וַתִּקָּחֶֽהָ
И пошла дочь фараона, чтобы искупаться в реке; и ее девы шли вдоль берега реки; и она увидела ковчег среди флагов и послала свою служанку за ней.
Rashi
לרחץ על היאר — Invert the order of the words in this verse and then explain it: “The daughter of Pharaoh went down על היאר, by the river, לרחץ to bathe in it”.
Chizkuni
לרחוץ על היאור, “to bathe in the waters of the river; other examples of the word על meaning “in,” instead of “on, or above,” are found in: Genesis 27,40 על חרבך תחיה, “you will live with the use of your sword.” Also Exodus 12,7: על הבתים אשר יאכלו אותו בהם, “in the houses that they will eat it in.
Da'at Zekenim
ותשלח את אמתה, “she sent her handmaid (to fetch it).” In the Talmud, tractate Sotah folio 12, two sages disagree concerning the meaning of the word אמתה here, one claiming that it refers to her forearm, (The princess’;) According to one sage this was a bodily owned slave, שפחה, whereas the other sage the princess went down to bathe on her own. [The author speculates how to reconcile the opinion of the sage who claimed that she sent forth a slave with the aggadic statement that an angel struck down all but one of her slaves at the time. [This editor does not follow the need for these far fetched interpretations, and I have not pursued them further. Ed.]