The central message of this sermon is that God's promises are often fulfilled in ways that do not align with human expectations or timelines. Despite David's years of struggle, hardship, and waiting, God ultimately kept His promise to make David His king over all Israel. The sermon highlights three key lessons learned from David's life: understanding the promise as it is given (not reading more or less into it), trusting God to do what He says He will do, and obeying God in response to His promises. These lessons are not unique to David's story but can be applied broadly, including to Abram's experience in Genesis 12-15, where he trusted God for a promise that seemed impossible at his age. The sermon emphasizes the importance of trusting God's sovereignty and timing, rather than relying on human efforts or expectations.