Both liberal and evangelical scholars have entertained doubts about the presence and/or frequency of conversion in the OT, but the doctrine is illustrated and objectified in the OT rather than being presented in doctrinal discourses as in the NT. Moses spoke of conversion in terms of the circumcision of the heart in Deut 10:16 and 30:6. The OT prophets referred often to Deuteronomic theology found in Deut 27-30 as a foundation for their prophecies. Joshua spoke of fearing the Lord in developing the Deuteronomic basis for conversion. Hezekiah’s trust in the Lord also built on that foundation, and the prophets after him continued to build thereon. Examples of conversion in the OT included Abram, Naaman, Rahab, Ruth, the sailors on board the ship with Jonah, and the Ninevites. Elements involved in conversion in the OT included the Holy Spirit, the Word of God, knowledge of God, confession, faith, and repentance. A total change in a person’s life was the obvious outcome of conversion.
Read this article from the Masters Seminary Journal in PDF format here.