Musar על נדרים 40:1

Not only that but even at the fitting hour and proper time they said of Rabbi Eliezer: "he uncovers a handbreadth and conceals two, and acted as though he were compelled by a demon" (Nedarim 20b), in order to not derive pleasure then.

This is as they said regarding Rabbi Eliezer: "he would expose one handbreadth and conceal two, and was as one compelled by a demon" (Nedarim 20b). He would not derive any enjoyment whatsoever, and would perform the act only with intent to the mitzva and divine service. Shlomo said on this: "Know Him in all your ways, and He will straighten your paths" (Mishlei 3:6).