When betrothing a woman, the groom says "Behold, you are betrothed to me with this ring, according to the tradition of Moshe and Israel."
As explained in that article, "according to the tradition of Moshe and Israel" means according to the Torah. (See Tosfot Ketubot 3A dh Adata.)
As Rabbi Maurice Lamm puts it, Jewish marriage ... must follow the process ordained by "the laws of Moses," which he received on Mount Sinai, and "of Israel," the Oral Law as developed by the teachers in the Talmud, Codes, and Responsa.
If "Moshe" refers to Biblical Law, and "Israel" refers to Rabbinical Law, so why not say so explicitly? What is the significance of 'Moshe' and 'Israel'?