“Then shall I have an answer for him who taunts me, for I trust in your word.”
This refers back to verse 41, and is truly the unanswerable answer. When God gives us salvation, and when we are confident that He loves us in Christ, we are at total peace. There is nothing greater than being in good standing with the Creator of the universe. When we have this eternal confidence, we are ready to answer the objections of those who oppose us.