출애굽기 8:18의 주석

והפליתי means I WILL SEPARATE. Similar is, (Exodus 9:4) “And the Lord will make a separation (והפלה)”; so, also, (Deuteronomy 30:11) “It is not נפלאת from thee״ — that is, “it is not separated and set at a far distance from thee”.

AND I WILL SET APART IN THAT DAY THE LAND OF GOSHEN. Due to the fact that the first plagues were not migratory in nature, it was no wonder that they were confined to the land of Egypt and were not to be in the land of Goshen, [Israel’s habitation].¹⁸⁴Genesis 47:15. But this [plague of swarms] was a migratory plague. Thus when the wild beasts came up from the lions’ dens, from the mountains of the leopards,¹⁸⁵Song of Songs 4:8. and brought ruin upon the whole land of Egypt, it was natural that they also come into the land of Goshen, which contained some of the best of the land of Egypt.¹⁸⁶See Genesis 47:6, where the land of Goshen is referred to as the best of the land of Egypt. Therefore it was necessary for Him to say, And I will set apart in that day the land of Goshen, so that it would be completely saved [from the wild beasts] because My people dwell in it, as the majority of its inhabitants were Israelites.
And I will put ‘p’duth’ (a division) between My people and thy people.¹⁸⁷Verse 19. The intent thereof is that even in the land of Egypt, if the beasts will find a certain Jew, they will not harm him. Instead they will devour the Egyptians, as it is written: He sent among them swarms of beasts, which devoured them.¹⁸⁸Psalms 78:45. This is the sense of the word ‘p’duth’ between My people and thy people, which is similar to the verse, I have given Egypt as thy ransom, Ethiopia and Seba for thee.¹⁸⁹Isaiah 43:3.

והפלאתי ביום ההוא, seeing that these wild beasts are fleet-footed and would invade any kingdom without regard to international borders once the plague has been released, the Torah had to stress that it would be observed that these animals would respect the unfenced areas in which the Jews were living as if they were physical obstacles. The same phenomenon would be observed when the “natural” disaster which struck the herds under the heading of דבר, the fifth plague, did not infect a single animal owned by the Israelites.