Deuteronomy 6:6

— What is the “love” that is here commanded? The next verse tells us: והיו הדברים האלה THESE WORDS [WHICH I COMMAND THEE] SHALL BE [UPON THINE HEART] — for thereby thou wilt arrive at a recognition of the Holy One, blessed be He, and wilt cleave to His ways (Sifrei Devarim 33:1). אשר אנכי מצוך היום [THESE WORDS] WHICH I COMMAND THEE THIS DAY — this day— they should not be in thine eyes as an antiquated דיוטגמא which no one minds, but as one newly given which everyone gladly welcomes (Sifrei Devarim 33:2; cf. our first Note on p. 248 in the Silbermann edition of Exodus). — The word דיוטגמא in this Midrash signifies: a royal command committed to writing.

וְהָי֞וּ הַדְּבָרִ֣ים הָאֵ֗לֶּה אֲשֶׁ֨ר אָנֹכִ֧י מְצַוְּךָ֛ הַיּ֖וֹם עַל־לְבָבֶֽךָ׃

And these words, which I command thee this day, shall be in thy heart: