Commentaire sur Les Nombres 20:15

וירעו לנו AND [THE EGYPTIANS] DID EVIL TO US — we have borne many adversities.

ולאבותנו, “and to our forefathers,” this was a reference to the Israelites who, though enslaved in Egypt, had not lived long enough to experience the redemption. According to our sages in Tanchuma Chukat 12, the word is a direct reference to the patriarchs, all of whom are described as participating in the pain of the enslavement their offspring had endured in Egypt even in their graves.

We endured much suffering. (Gur Aryeh) Though the term וירעו ["they mistreated"] merely implies that they did one evil act to them, but elsewhere (Devarim 26:6) it is written, “They mistreated us and afflicted us…” Therefore Rashi explains that וירעו includes much suffering, and thus all afflictions are included.