The title "King of Judah" refers to the monarchs who ruled over the southern kingdom of Judah following the division of the united monarchy of Israel after the reign of King Solomon. This division resulted in two separate kingdoms: the northern kingdom, known as Israel, and the southern kingdom, known as Judah. The kings of Judah were descendants of King David, fulfilling God's promise that David's lineage would continue to rule (2 Samuel 7:16).

Rehoboam
Rehoboam, the son of Solomon, was the first king of Judah. His reign marked the beginning of the divided kingdom. Rehoboam's harsh policies led to the secession of the ten northern tribes, forming the kingdom of Israel (1 Kings 12:16-17). Despite his initial failure to maintain the united monarchy, Rehoboam fortified cities and strengthened Judah's defenses (2 Chronicles 11:5-12).

Jehoshaphat
Jehoshaphat, the son of Asa, was noted for his faithfulness to God and his efforts to rid Judah of idolatry. He sought to follow the ways of David and established a system of judges to uphold justice (2 Chronicles 19:4-7). Jehoshaphat also formed an alliance with Ahab, king of Israel, which led to military cooperation but also spiritual compromise (1 Kings 22:4).

Hezekiah
Hezekiah, the son of Ahaz, was a reformer king who trusted in the Lord and sought to restore proper worship in Judah. He removed high places, smashed sacred stones, and cut down Asherah poles (2 Kings 18:4). Hezekiah's faith was tested when the Assyrian king Sennacherib invaded Judah, but Hezekiah's prayer and reliance on God led to a miraculous deliverance (2 Kings 19:35-36).

Josiah
Josiah, the son of Amon, became king at a young age and was known for his zealous reforms. He rediscovered the Book of the Law during temple repairs and initiated a national renewal of the covenant with God (2 Kings 22:8-13). Josiah's reforms included the removal of idolatrous practices and the reinstitution of the Passover (2 Kings 23:21-23).

Zedekiah
Zedekiah, the last king of Judah, reigned during a tumultuous period that culminated in the Babylonian conquest. Despite warnings from the prophet Jeremiah, Zedekiah rebelled against Babylon, leading to the destruction of Jerusalem and the temple in 586 BC (2 Kings 25:1-10). His reign marked the end of the Davidic monarchy until the prophesied restoration.

Spiritual Significance
The kings of Judah played a crucial role in the spiritual life of the nation. Their faithfulness or unfaithfulness to God had direct consequences for the people. The Davidic line of kings is significant in biblical prophecy, pointing to the coming of the Messiah, Jesus Christ, who is referred to as the "Son of David" (Matthew 1:1). The kingship of Judah thus serves as a foreshadowing of Christ's eternal reign.