ATTAH EḤAD (Heb. אַתָּה אֶחָד; "Thou art One"), name of the central section of the Sabbath afternoon *Amidah. The prayer emphasizes the Oneness of God: "Thou art One, Thy Name is One," and the uniqueness of Israel: "and who is like Thy people Israel, a nation one on earth" (i Chron. 17:21). In the prayer, the Sabbath is called "a crown of distinction and salvation" which God gave to His people as a day of rest and holiness. The patriarchs Abraham, Isaac, and Jacob all found joy and rest on the Sabbath. The prayer closes with the invocation: "May Thy children know that from Thee cometh their rest, and by their rest they hallow Thy name." This prayer, which originated with the geonim (eighth–tenth century c.e.), is based upon the Midrash (cf. Tos. Ḥag. 3b) that God, Israel, and the Sabbath mutually testify to the Oneness of God, the peerlessness of Israel His people, and the uniqueness of the Sabbath as a day of holy rest.