'Saith' in the Bible

Go and tell David my servant, Thus saith Jehovah, Thou shalt not build me a house to dwell in:

Now therefore thus shalt thou say unto my servant David, Thus saith Jehovah of hosts, I took thee from the sheepcote, from following the sheep, that thou shouldest be prince over my people Israel:

Go and speak unto David, saying, Thus saith Jehovah, I offer thee three things: choose thee one of them, that I may do it unto thee.

So Gad came to David, and said unto him, Thus saith Jehovah, Take which thou wilt: