Mishnah Yadayim 3:2: Anything that invalidates terumah [a portion of a crop which must be given to a priest, and can only be consumed by priests or their household] renders the hands to be of a secondary [degree of] impurity. One hand renders its fellow [hand] impure, according to Rabbi Yehoshua. And the Sages say: something [of a] secondary [degree of impurity] cannot render something to be [of a] secondary [degree of impurity]. He said to them: Are not sacred scriptures [of a] secondary [degree of impurity], and they render hands to be impure [with a secondary degree of impurity]!? They said to him: we cannot infer Words of Torah [i.e. laws in the written Torah] from Words of Scholars [i.e. laws in the oral Torah], nor Words of Scholars from Words of Torah, nor Words of Scholars from Words of Scholars.

כֹּל הַפּוֹסֵל אֶת הַתְּרוּמָה, מְטַמֵּא אֶת הַיָּדַיִם לִהְיוֹת שְׁנִיּוֹת. הַיָּד מְטַמְּאָה אֶת חֲבֶרְתָּהּ, דִּבְרֵי רַבִּי יְהוֹשֻׁעַ. וַחֲכָמִים אוֹמְרִים, אֵין שֵׁנִי עוֹשֶׂה שֵׁנִי. אָמַר לָהֶם, וַהֲלֹא כִתְבֵי הַקֹּדֶשׁ שְׁנִיִּים מְטַמְּאִין אֶת הַיָּדַיִם. אָמְרוּ לוֹ, אֵין דָּנִין דִּבְרֵי תוֹרָה מִדִּבְרֵי סוֹפְרִים, וְלֹא דִבְרֵי סוֹפְרִים מִדִּבְרֵי תוֹרָה, וְלֹא דִבְרֵי סוֹפְרִים מִדִּבְרֵי סוֹפְרִים:

Mishnah Yadayim 3:3: Tefillin straps with the Tefillin render the hands impure. Rabbi Shimon says: Tefillin straps do not render the hands impure.

רְצוּעוֹת תְּפִלִּין עִם הַתְּפִלִּין, מְטַמְּאוֹת אֶת הַיָּדַיִם. רַבִּי שִׁמְעוֹן אוֹמֵר, רְצוּעוֹת תְּפִלִּין אֵינָן מְטַמְּאוֹת אֶת הַיָּדַיִם: