Exodus 4:9

והיו המים וגו׳ — Here we have the word והיו twice. It appears to me that if it was stated היאר לדם ביבשת מן והיו המים אשר תקח, I might understand it to mean that it would be turned into blood in his hand and that also when it reached the ground it would retain that state (more lit., it would be as it was). But now (as the text stands) it tells us that it would not become blood until it would come on the dry ground.

וְהָיָ֡ה אִם־לֹ֣א יַאֲמִ֡ינוּ גַּם֩ לִשְׁנֵ֨י הָאֹת֜וֹת הָאֵ֗לֶּה וְלֹ֤א יִשְׁמְעוּן֙ לְקֹלֶ֔ךָ וְלָקַחְתָּ֙ מִמֵּימֵ֣י הַיְאֹ֔ר וְשָׁפַכְתָּ֖ הַיַּבָּשָׁ֑ה וְהָי֤וּ הַמַּ֙יִם֙ אֲשֶׁ֣ר תִּקַּ֣ח מִן־הַיְאֹ֔ר וְהָי֥וּ לְדָ֖ם בַּיַּבָּֽשֶׁת׃

And it shall come to pass, if they will not believe even these two signs, nor hearken to thy voice, that thou shalt take of the water of the River, and pour it upon the dry land: and the water which thou dost take out of the River shall become blood on the dry land.