דברים, פרק כ״ח, פסוק ס׳

The threat of disaster draws upon a deep historical trauma, using the vivid memory of the plagues in Egypt as a powerful deterrent against abandoning God's path. Mentioning these specific diseases and afflictions is not accidental, as the plagues represent God's harshest judgments [ביאור יש״ר, ביאור שטיינזלץ]. This creates an ironic and tragic cycle. The very illnesses that were originally brought upon the Egyptians for the sake of the Israelites will turn back and strike the Israelites themselves [בכור שור].

The warning emphasizes that these are afflictions the people already deeply feared. When the Israelites witnessed the strange plagues striking Egypt up close, they were filled with terror, afraid that they too might be harmed by them [רש״י, ביאור שטיינזלץ]. This intense fear was not directed at the Egyptian nation, but rather at the terrifying diseases themselves [שפתי חכמים]. In fact, these types of illnesses naturally exist in the Land of Israel and were a constant source of anxiety, but God had promised to protect the people from them [העמק דבר].

God uses this existential anxiety as a warning, operating on the principle that a person can only be truly threatened by something they already fear [רש״י]. When the people stray from God's path, His divine protection is removed, allowing the very diseases they dreaded to materialize and strike [רלב״ג]. Ultimately, these afflictions will come and attach themselves directly to the people [ביאור שטיינזלץ]. However, some view this attachment in a strictly literal and restricted sense, suggesting that the diseases will only stick to the surface of the skin, without penetrating the inner flesh and bodies of the sinners [שפתי כהן].