The answer is: 70

2 Sam 5:4; 1 Ki 2:10-11

David, known as one of the most significant figures in Biblical history, lived a life that was as vibrant as it was tumultuous. When he died at the age of 70, he left behind an impressive legacy as a warrior, poet, and king. His age at death might seem ordinary today, but in a time when life was often shorter due to disease and hardship, his life encapsulated a profound impact on the people of Israel.

It's fairly intriguing to note that David's journey was marked not only by victories but also by deep personal trials. From shepherding sheep to defeating the giant Goliath and later establishing Jerusalem as the capital, he exemplified rising to greatness against the odds. His contributions were broader than his kingship; he’s credited with authoring many of the Psalms, filled with heartfelt poetry addressing struggles, repentance, and thanksgiving, much of which echoes through centuries to touch countless lives.

Moreover, there's a remarkable connection between David and the verse of his demise in 1 Kings 2:10-11, which underscores the legacy of monarchy in Israel. The mention of David's resting with his ancestors symbolizes a passage of continuity and divine heritage. Historically, many kings in the ancient world were measured not only by their rule but often by their familial and spiritual connections.

David’s complex narrative showcases that even great leaders have their shadows. Whether through loyalty to friends like Jonathan or failure like in the case of Bathsheba, he reminds us that wisdom and failure coexist, each offering lessons worth exploring.