וּלְכֹ֣ל ׀ בְּנֵ֣י יִשְׂרָאֵ֗ל לֹ֤א יֶֽחֱרַץ־כֶּ֙לֶב֙ לְשֹׁנ֔וֹ לְמֵאִ֖ישׁ וְעַד־בְּהֵמָ֑ה לְמַ֙עַן֙ תֵּֽדְע֔וּן אֲשֶׁר֙ יַפְלֶ֣ה יְהוָ֔ה בֵּ֥ין מִצְרַ֖יִם וּבֵ֥ין יִשְׂרָאֵֽל׃
但對所有以色列人，無論是人還是牲畜，連一條狗也不會向他們吐舌狂吠，好讓你們知道永恆者把埃及和以色列區分開來。
Rashi
לא יחרץ כלב לשנו NO DOG SHALL חרץ HIS TONGUE — I say that it has the meaning of sharpening: “no dog shall whet his tongue”. So, too: (Joshua 10:21) “לא חרץ his tongue against any of the children of Israel”, i. e. “none whetted”; (II Samuel 5:24) “then תחרץ” — then thou shalt utter a sharp sound; (Isaiah 41:15) “a threshing-sledge חרוץ” i. e. sharp; (Proverbs 21:5) “the plans of a חרוץ” — of “an acute and sharp man”; (Proverbs 10:4) “the hand of the חרוצים maketh rich”, i. e. the hand of the acute — of sharp merchants.
Rashbam
לא יחרץ כלב, the angel proceeds to afflict and kill the firstborn of the Egyptians. By contrast, the Jewish firstborn did not even have to endure the barking of a dog.
Or HaChaim
ולכל בני ישראל לא יחרץ כלב לשונו, "not a single dog will whet his tongue against any Israelite, etc." Why was this so important? If the meaning of the line is that not a single Israelite would die as a result of a bite by a dog, why did the Torah not spell this out?