וַיִּקַּח֩ אֵלִיָּ֨הוּ אֶת־אַדַּרְתּ֤וֹ וַיִּגְלֹם֙ וַיַּכֶּ֣ה אֶת־הַמַּ֔יִם וַיֵּחָצ֖וּ הֵ֣נָּה וָהֵ֑נָּה וַיַּעַבְר֥וּ שְׁנֵיהֶ֖ם בֶּחָרָבָֽה׃
And Elijah took his mantle, and wrapped it together, and smote the waters, and they were divided hither and thither, so that they two went over on dry ground.
Sforno
ונטה את ידך על הים, so that the waters will split to the two opposite sides of the shore, similar to what the prophet Elijah would do in Kings II 2,8.