Komentarz do Powtórzonego Prawa 25:18

אשר קרך בדרך HOW HE MET THEE BY THE WAY — The word קרך is connected in meaning with מקרה “a sudden happening”, i.e., he came against thee by surprise. Another explanation is: it is connected in meaning with the term קרי, nocturnal pollution and uncleanness, because he polluted them by pederasty. Yet another explanation is that it is connected in meaning with the expression קור in the phrase קור וחום “cold and heat” and it means: he made you cold and lukewarm after the boiling heat you had before. For all the nations were afraid to war against you and this one came and began to point out the way to others. A parable! It may be compared to a boiling hot bath into which no living creature could descend. A good-for-nothing came, and sprang down into it; although he scalded himself he made it appear cold to others (Midrash Tanchuma, Ki Teitzei 9).

אשר קרך בדרך, "who happened to you on the way, etc." This expression may be understood on the basis of Rosh Hashanah 3 where we are told that the cloud of G'd was continuously enveloping the Israelites so that no one knew the exact whereabouts of this people until the death of Aaron when this cloud dissipated. At that time the Canaanite (Amalekites dressed up as Canaanites) attacked the Israelites. In view of this, how did the Amalekites locate the encampment of the Israelites? To answer this question the Torah writes אשר קרך בדרך, "who chanced upon you on the way." The Torah goes on with ויזנב בך, "and he struck your hindmost ones, the ones who trailed behind." The Torah means that the cloud did not permit the Amalekites to penetrate into the camp of the Israelites; however, they struck only those whom the cloud had expelled as unfit for this kind of protection. When the Torah speaks of הנחשלים אחריך, "the weaklings behind you," it refers to the spiritually weak Israelites.

אשר קרך בדרך, meaning “accidentally,” unforeseen. The construction קרך from the root קרה is parallel to the construction עשך from the root עשה, Deut. 32,6 הוא עשך ויכוננך, “He has shaped you and made you durable.”