David was thirty years old when he became king, and he reigned forty years. In Hebron he reigned over Judah seven years and six months, and in
Jerusalem he reigned over all Israel and Judah thirty-three years. 2 Samuel 5:4-5 (TM)
One of the things we easily forget is that there was at least twenty years between David being anointed King by Samuel and when he became King of all Israel. In that twenty years David was hunted by his own King, survived like a fugitive in the desert, and fought for his enemies. It’s not uncommon for a season of wilderness to exist between God’s promise and its’ fruition. It’s the wilderness that prepares us for the Promise.