'Believer' in the Bible

Paul came also to Derbe and to Lystra. And a disciple was there, named Timothy, the son of a Jewish woman who was a believer, but his father was a Greek,

Or what harmony has Christ with Belial, or what has a believer in common with an unbeliever?

So then those who are of faith are blessed with Abraham, the believer.

If any woman who is a believer has dependent widows, she must assist them and the church must not be burdened, so that it may assist those who are widows indeed.