1 corinthians 1v2 "to the church of God in Corinth, to those sanctified in Christ Jesus and called to be holy (literal translation: have been made holy), together with all those everywhere who call on the name of our Lord Jesus Christ - their Lord and ours"
How would you feel if I said, "I'm a saint!"?
You'd think, "that's an arrogant thing to say".
That's because we associate being a saint with doing good. So if I say I'm a saint, you think I'm saying a good person.
But Scripture says being a saint is quite the opposite - it is absolutely nothing to do with what we do, but it is something given to us, regardless of what we do. It is something available to anyone who calls on the name of our Lord Jesus Christ. So if I trust in Christ, God considers me a saint!