What do JWs bear witness to concerning Jesus? That Jehovah will save obedient mankind by means of Jesus. That is the meaning of the name Jesus = Jehovah saves. To bear witness concerning Jesus is to witness to Jehovah and him saving mankind. Jesus himself is called the faithful and true witness. Acts says that Jehovah would gather a people from the nations, “called by my name”. Why don’t churches of Christendom point out that the name Jesus means “Jehovah saves” or call themselves by God’s unique personal name as stated in Acts?
Acts 15:14–18 Symʹe·on has related thoroughly how God for the first time turned his attention to the nations to take out of them a people for his name. And with this the words of the Prophets agree, just as it is written: ‘After these things I will return and raise up again the tent of David that is fallen down; I will rebuild its ruins and restore it, so that the men who remain may earnestly seek Jehovah, together with people of all the nations, people who are called by my name, says Jehovah, who is doing these things, known from of old.’
Rev 3:14 “To the angel of the congregation in La·o·di·ceʹa write: These are the things that the Amen says, the faithful and true witness, the beginning of the creation by God
Matt 1:21 She will give birth to a son, and you are to name him Jesus, for he will save his people from their sins.”
