That is the essential difference in Dispensational theology and non-dispensational theology.
In the church age, when a gentile or jew believes in Christ he becomes a Christian (a member of the Body of Christ)
All of those who became before the Church age (Acts 2), (friends of the Bride) were either saved gentiles (Enoch, Noah, Job) or saved Jews.
When the Church is removed, when one believes in the Tribulation period (a resumption of the Jewish age-Daniels 70th week) one will be either a saved Jew or Gentile, not a Christian.
Only in this dispensation are there three groups of people, Gentile, Jew and Church (saved)(1Cor.10:32)