1 Samuel 17:56

And the king said, Enquire thou whose son the stripling is.

The question about the stripling arises when David arrives at Saul's camp while Israel stands facing Goliath. He has come at his father's direction to visit his brothers, yet he is also sent to save Israel, and his zeal is stirred when he sees the people afraid and hears Goliath defying God and Israel. The stripling the king asks about is David himself, a mere youth who tends sheep rather than a warrior, whose strength lies in humble trust in the Lord God of Israel.

In this setting Saul's armor represents humanly prepared arguments, which must be laid aside as unproved and untrusted, with trust placed in God to give truth the victory. Goliath represents a confident, boastful defier who provokes discussion, magnifies self, and does not hide behind Jesus, a part that belongs to opposers of truth and not to ministers. Applied to discussion of truth, going forth like David means not defying and provoking discussion but humbling the heart in faith and relying wholly on God, while going forth like Goliath in self-confidence and elation makes discussions unsuccessful and injures one's own soul and the souls of others.