God uses our testimonies to defeat the enemy

Scripture reference

Revelation 12:11 (ASV 1901)

11And they overcame him because of the blood of the Lamb, and because of the word of their testimony; and they loved not their life even unto death.

Stories

Just by reading the many amazing stories of faith, trust in God and answers to prayers contained in George Müller's Narrative of the Lord's dealings with him, many Christians had their faith in God strengthened, some were encouraged to give to God, and even unbelievers were drawn to Him.