וַיִּשְׁלַ֣ח פַּרְעֹ֔ה וְהִנֵּ֗ה לֹא־מֵ֛ת מִמִּקְנֵ֥ה יִשְׂרָאֵ֖ל עַד־אֶחָ֑ד וַיִּכְבַּד֙ לֵ֣ב פַּרְעֹ֔ה וְלֹ֥א שִׁלַּ֖ח אֶת־הָעָֽם׃ (פ)
Pharao schickte nun hin und [sah], es war von dem Vieh Israels auch nicht eines gestorben; doch das Herz Pharaos blieb verstockt und er ließ das Volk nicht ziehen.
Chizkuni
וישלח פרעה והנה לא מת, “Pharaoh dispatched people to check on the livestock of the Israelites, and not a single one had died.” The reason for this was Moses’ prediction in verse 4 that G-d will make this distinction between Egyptian and Israelite owned beasts.
Chizkuni
ויכבד לבו; “but his heart remained obstinate;” he did not ask Moses to pray, as the dead beasts could not be brought back to life. The beasts that had survived did not need to be prayed for.