For how many years did David reign as king over the United Kingdom of Israel?

David reigned as king over the United Kingdom of Israel for a total of 40 years. This includes a period of seven years in Hebron, where he ruled over Judah, followed by 33 years in Jerusalem, where he governed all of Israel. The biblical account, particularly in books like 2 Samuel, outlines the timeline of his reign, confirming that David's leadership spanned these two significant phases. The choice indicating 33 years only accounts for his time as king of all Israel in Jerusalem, not considering his earlier reign in Hebron, which is why the correct total is often cited as 40 years when assessing his entire rule.