Who Are Called - Romans 1:5-6

Romans 1:5-6 ESV
through whom we have received grace and apostleship to bring about the obedience of faith for the sake of his name among all the nations, including you who are called to belong to Jesus Christ,

The Greek word translated as "called" includes the sense of invitation. God extends His mercy to all. Those that answer enter into the body of Christ. They become the called, the saints, and the Bride of Christ. It is the offer and acceptance that constitute being called.

Peter seems to tell us our calling initiates a walk that leads to the eternal kingdom. Jesus is the way. Stay true to that path.

κλητοσ kletos 10x called, invited, in NT called to privileges or function, (MCGDON)

2 Peter 1:10-11
Therefore, brethren, be all the more diligent to make certain about His calling and choosing you; for as long as you practice these things, you will never stumble; for in this way the entrance into the eternal kingdom of our Lord and Savior Jesus Christ will be abundantly supplied to you.