The answer is: Judah

1 Kings 12:20 - Following Solomon's reign, the nation divided into two distinct kingdoms: Israel in the north and Judah in the south. The southern kingdom, Judah, held great significance as it was the lineage of David and ultimately where Jerusalem is located, playing a central role in biblical history.

The division of the nation after Solomon's reign marks one of the pivotal moments in Israelite history. Upon this split, Israel and Judah not only formed two separate political entities but also followed different paths, each with unique kings and prophetic voices. The term "Judah" means "praise," which feels particularly fitting since it is associated with the lineage of King David—and subsequently, the Messianic line in Christian tradition.

Perhaps interestingly, the southern kingdom of Judah stood out in several respects. While Israel had a plethora of kings, many of whom were unfaithful to God, Judah boasted a number of kings who made 'right judgments' and rejuvenated the spiritual life of their people. Kings like Hezekiah and Josiah are well-remembered for leading religious reforms that aimed to restore the worship tradition as outlined in earlier scriptures.

An intriguing historical echo is how the city of Jerusalem served as the capital of Judah and is revered today for being a focal point of three major world religions. The Temple of Solomon—built during David's time—remained in Jerusalem, serving as a sacred space until its destruction and the subsequent Babylonian exile.

One unique aspect to keep in mind is how this split led to varied prophetic activity—including the notorious messages from the prophet Elijah in Israel, contrasting with Jeremiah and Isaiah, who were active in Judah. Through these prophets, the two kingdoms navigated their distinctly challenging landscapes while influencing theological concepts that persist through various interpretations into the present day.