וּקְשַׁרְתָּ֥ם לְא֖וֹת עַל־יָדֶ֑ךָ וְהָי֥וּ לְטֹטָפֹ֖ת בֵּ֥ין עֵינֶֽיךָ׃
I nawiążesz je jako znak na rękę twoję, i niechaj będą przepaską między oczyma twojemi.
Mishnah Sanhedrin
There is greater stringency in respect to the teachings of the scribes than in respect to the torah: [thus,] if [a rebellious elder] says, there is no commandment of tefillin, so that a biblical law may be transgressed, he is exempt. [But if he rules that the tefillin must contain] five compartments, thus adding to the words of the scribes, he is liable.