Is this an unscriptural and sectarian (divisive) notion?
The word Christian/s appears only 3 times in scripture.
Footnotes (for these 3 scriptures) in the Aramaic English Bible (by Andrew Gabriel Roth) say that this label came from outside and was not used between believers or by the apostles in reference to themselves.
One imagines Paul saying there is neither Jew, nor Christian, nor Muslim, nor Hindu...