Answer
The Bible gives no indication that finger rings were used as betrothal or nuptial rings. The signet ring is the earliest type of ring mentioned in the Bible. In fact, when Abraham’s servant found Rebekah, he gave her a nose ring to claim her as Isaac’s bride (Genesis 24:22)! When Tamar disguised herself as a harlot to entice her father-in-law, Judah, she asked him for his signet, cord, and staff as a pledge of his promise to send her "a kid from the flock" (Genesis 38:17-19). Jeremiah informs us that the Israelites wore the signet ring on the right hand (Jeremiah 22:24). The signet ring was used to seal various contracts. It was a symbol of authority, dignity, and social status (James 2:2). Pharaoh gave his signet ring to Joseph as a symbol of authority (Genesis 41:42). Likewise, Ahasuerus gave his signet to Haman to seal a royal decree (Esther 3:10, 12). Upon his return, the prodigal son received a ring from his father as a symbol of dignity and restored position (Luke 15:22).
The finger rings mentioned in the Bible are signet rings used as symbols of authority and dignity. The Romans are credited for pioneering the use of the signet ring as a betrothal ring. The Jews and the Christians borrowed the practice from the Romans. Since the betrothal ceremony usually involved the groom giving a sum of money or a valuable object to the bride, it was a natural transition to make this object a ring.
The wedding or marriage ring came into use in Christian ceremonies in the 9th century AD. The custom of wearing the wedding ring on the fourth finger of the left hand is based upon a romantic, although unscientific, Greek fable that the artery from that finger flows directly to the heart. However and whenever the custom of the wedding band developed, it is seen today as a symbol of an unending commitment to the marriage relationship. As such, it certainly has a biblical basis in that marriage is to be a lifetime commitment (Romans 7:2). This is not to say that wearing a wedding ring is a requirement for married Christians. But wedding rings are a beautiful reminder of the marriage covenant and, by extension, the covenant of Christ with His bride—the redeemed for whom He died.