Musar for Shabbat 23:3

אלא אביי ורבא דאמרי תרווייהו ל"ק הא ר' יהודה והא ר' שמעון

— Rather, said both Abaye and Raba, There is no difficulty: the one is according to R. Judah; the other agrees with R. Simeon.<span class="x" onmousemove="('comment',' R. Judah maintains that one is culpable for an act even if that which necessitates it is undesired; while R. Simeon holds that there is no liability for such. Thus, here the carrying of the pouch is necessitated by the discharge, but the discharge itself is certainly unwanted. ');">⁵</span> The School of R. Ishmael taught: A man may go out with his tefillin<span class="x" onmousemove="('comment',' V. Glos. phylacteries. ');">⁶</span>

Mesilat Yesharim