There are numerous reasons, but perhaps the most powerful is that which affects us on a personal level. For instance David trusted God's Word from his youth up. His recommendation is:
(Psalm 34:8) Taste and see that Jehovah is good; Happy is the man who takes refuge in him.
He composed that Psalm in appreciation for his rescue from a sticky situation.
Psalm 34:superscription-22) Of David, when he disguised his sanity before A·bimʹe·lech, who drove him away, and he left.
1 Samuel 21:10-15.
Many others have had similar experiences in their lives.
