Reference for Eruvin 190:22
ורבן גמליאל סבר לא בעי כוונה
And if you prefer I might reply that all agree that the Sabbath is a time for tefillin,<span class="x" onmousemove="('comment',' And also, that tefillin may be regarded as an ornament that may be worn on the Sabbath in a public domain.');"><sup>42</sup></span> but here the point at issue between them<span class="x" onmousemove="('comment',' R. Gamaliel and the first Tanna in our MISHNAH:');"><sup>39</sup></span> is whether the performance of commandments requires intention, the first Tanna holding that in order to discharge the duty of a commandment, intention is not<span class="x" onmousemove="('comment',' This is the reading according to MS.M. and Rashi's second interpretation. Cur. edd. 'is necessary'.');"><sup>43</sup></span> necessary<span class="x" onmousemove="('comment',' If, therefore, a man puts on tefillin he performs the commandment ipso facto. Consequently he may wear only one pair at a time. For, should he wear more than one pair, whatever his intention, he would be transgressing the prohibition against adding to the commandments (v. infra n. 13) .');"><sup>44</sup></span> while R'Gamaliel holds that intention is<span class="x" onmousemove="('comment',' So with MS.M. and Rashi's second interpretation. Cur. edd., 'is not'.');"><sup>45</sup></span> necessary.<span class="x" onmousemove="('comment',' Hence it is possible to wear two pairs of tefillin as ornaments (cf. Supra n. 8) without transgressing the prohibition against 'adding to the commandments' (cf supra n. 10) .');"><sup>46</sup></span>