Question: Currently we are studying the Sermon on the Mt. The question arose as to why Jesus said “truly I say to you.” I know in the KJV the actual word was verily, but why that word?
Answer: The word is from the Hebrew and is literally “amen,” but when used at the beginning of a statement as Jesus does, it can be translated “truly.” Jesus is the only one who uses it this way in the New Testament. The writer of the article in the Dictionary of New Testament Theology said, “By introducing his words with amen Jesus labeled them as certain and reliable. He stood by them and made them binding on himself and his hearers. They are an expression of his majesty and authority.”
Jesus often makes such statements, as he does in the Sermon on the Mount, as contrasts with the way the Law of Moses has been typically interpreted. Consequently he is setting up his interpretation as authoritative over against the Scribes, Pharisees and Sadducees.
Plummer writes, “He is evidently conscious of possessing this supreme authority, and it manifests itself quite naturally, not in studied phrases, but as the spontaneous expression of His habitual modes of thought. One who knew that He was the Messiah, and was conscious of His own absolute righteousness, would consistently, perhaps we may say, inevitably, speak in some such way as this.”