Talmud zu Schir haSchirim 6:4

Beloved are Israel [by God], for they observe all the commandments that are in the Torah. How? Tefillin on their hands, tefillin on their heads, a mezuzah on their doors and four ẓiẓith on their garments. Concerning them David, king of Israel, said, Seven times a day do I praise Thee, because of Thy righteous ordinances.⁹⁷Ps. 119, 164.
[The Sages] illustrated this with a parable. To what may this be compared? To a king who said to his wife, ‘Be well dressed and adorned in my presence’. ‘For what reason?’ she asked him. ‘In order that you may be acceptable to me,’ he replied. Similarly the Holy One, blessed be He, said to Israel, ‘My children, be well dressed and adorned in My presence with [your performance of] the commandments’. ‘For what reason?’ they asked Him. ‘In order,’ He replied, ‘that you may be acceptable to Me’; as it is stated, Thou art beautiful, O my love, as Tirẓah,⁹⁸Cant. 6, 4. [which means,] ‘Thou art beautiful when thou art acceptable⁹⁹Tirẓah is of the same root as raẓuï (acceptable). to Me through [thy performance of] the commandments’.