tabaath, "to impress with a seal." frontEARRING.) Used as "a signet" (Genesis 38:18, chothem), worn on the hand, or suspended, as the Arabs do, by a cord from the neck. Pharaoh's transfer of his ring from his finger to Joseph betokened his investing him with royal authority (Genesis 41:42; a device, as the beetle or the owner's name, was engraven on it, Exodus 28:11). So Ahasuerus in the case of Haman (Esther 3:8-10), and Mordecai (Esther 8:2). In Luke 15:22 it is the father's token of favor, dignity, and sonship to the prodigal; Roman slaves wore no gold rings. We are no longer slaves, but God's free sons when we believe, and receive the Holy Spirit as the pledge of sonship and earnest of sharing the Father's glory (Galatians 4:3-7). Rich men (especially Romans of the equestrian order, whose badge the ring was) wore many rings on the left hand (James 2:2). Greek "golden-ringed," not merely with one ring.
Christians derived the usage of the wedding ring from the Jews. The ring was treasured much, and so symbolizes what is most precious to us (Jeremiah 22:24, Jehoiachin's popularity is alluded to); the signet ring was worn on the right hand (contrast Haggai 2:23). A costly sacrifice to the Lord (Exodus 35:22). Song of Solomon 5:14, "his hands" bent are compared to "rings" in which "beryls" are set, as the nails in the fingers; compare as to our names being "sealed" upon His heart, Song of Solomon 8:6, and palms, Isaiah 49:16. The bride desires herself to be a signet ring on His arm. God in turn seals us with His signet (Revelation 7:2-4), "I will make thee as a signet" (Haggai 2:23), i.e. an object of constant regard, as the ring is ever before the eye. Christ the Antitype is always in the Father's presence, ever pleasing in His sight; so we, through Him our representative. The signet represents legally the owner; so Christ wields the Father's delegated authority (Matthew 28:18; John 5:22-23).
Fausset, Andrew Robert M.A., D.D., "Definition for 'ring' Fausset's Bible Dictionary".