1 Samuel 17:58
And Saul said to him, Whose son art thou, thou young man? And David answered, I am the son of thy servant Jesse the Beth-lehemite. And Saul said to him, Whose son art thou, thou young man? And David answered, I am the son of thy servant Jesse the Beth-lehemite.
The history surrounding Saul's question to David after the battle stands as a warning to God's servants in religious controversy not to take Goliath's place by issuing defiance, provoking debate, and marching out confident and boastful while exalting self instead of hiding behind Jesus. Saul's wish for David to put confidence in the king's armor stands for putting confidence in carefully prepared human arguments. David's refusal to go with armor he had not tested, and his trust instead in the God of Israel, shows what is required in discussion: to humble the heart, to make God the strength, and to trust Him to give the truth the victory.
To enter discussion in Goliath's spirit, in self-confidence and reliance on argument, lifts the speaker into elation and throws him off balance. That course makes discussions unsuccessful. It also does spiritual harm, injuring the soul of the one who speaks and the souls of those who listen.