Proverbs 22:21
"That I might make thee know the certainty of the words of truth; that thou mightest answer the words of truth to them that send unto thee?"
Cross References (ranked by relevance)
1 Peter 3:15
But sanctify the Lord God in your hearts: and be ready always to give an answer to every man that asketh you a reason of the hope that is in you with meekness and fear:
John 20:31
But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.