Honored of God

How and why does God cause His Word to prosper? What was the reason God honored Israel and David as king? Of all that God revealed in His Word did anything fail? How do we see that all that matters is Christ? Why did the LORD reveal Himself to Samuel in Shiloh by the Word of the LORD? Why does the LORD reveal Himself through His Son Jesus Christ only? Why is it that the chosen children of God need not prove themselves?