The disciples were called Christians first at Antioch.Then the teacher typically has his students turn to Isaiah 62:2b, which states:
You shall be called by a new name,At first glance, this concept makes sense: God promised the believers a new name; now we're known by the name "Christian".
Which the mouth of YHWH will name.
But when considering the context of Isaiah 62, I believe this idea does violence to the text of God's word. Reading just a couple of verses later, in verse 4, we find that whereas the believers were currently known as "Forsaken", and their land as "Desolate", the new name for believers would be "Hephzibah" ("My Delight Is in Her"), and the new name for their land would be "Beulah" ("Married").
It seems to me that the "new name" of Isaiah 62 is a poetic way of saying that believers have been like the lonely and sad woman who is "never a bride, always a bride's maid", but who would one day find happiness when she is finally loved and wedded.
To force-fit this passage as a prediction of a literal new name for believers, no matter how nice it sounds, is a mangling of the context of Isaiah.