וְשָׁמַרְתָּ֛ אֶת־הַחֻקָּ֥ה הַזֹּ֖את לְמוֹעֲדָ֑הּ מִיָּמִ֖ים יָמִֽימָה׃ (ס)
Targum Jonathan on Exodus
Thou shalt therefore keep this statute of the Tephillin in the season to which it belongs, on work days, not on sabbaths or solemnities; and by day, not by night.