The answer is: 40 years

1 Ki 2:11

David's reign indeed lasted for 40 years, a span that’s not just a number but rich with significance in biblical narratives. Split between two major phases—seven years in Hebron and thirty-three years in Jerusalem—David's rule was pivotal in the establishment of a central nation under God, laying the groundwork for both his son Solomon’s temple and Israel’s future.

An intriguing fact about the number 40 in the Bible is its deep connection to periods of trial, testing, and transition. From the 40 years the Israelites wandered in the desert to the 40 days of Jesus fasting in the wilderness, the number surfaces frequently, symbolizing profound transformation and experiences where reliance on divine guidance is paramount.

David’s kingship was vibrant and tumultuous, marked not only by military conquests and territorial expansion but also emotional struggles, such as those captured in his psalms—poems that vibrantly express despair, anger, joy, and repentance. That deep emotional tapestry shows us a flesh-and-blood leader more than just a figure of monarch status; he was a poet and a warrior.

Furthermore, Israel under David taken together with influential friendships, notably with Jonathan, showcases the powerful interplay of loyalty and love that defined David's life. It tells us about connections that shape legacies beyond political arrangements. These themes from David’s life resonate even today, as they reflect the enduring complexity of human leadership and frailty.