"called to be holy" or "called to saints" means to be called to be separated unto God, to live our lives to the glory of him who has so called us, it means been devoted to him who called us to be holy.GOD
Saints according to the Bible means those set apart unto God and those that believes in the Lord Jesus Christ and also call upo his name both those that died in Christ and those that are still living.
It's comfortable for us to say "l'm not a saint" because we tend to believe that our righteousness is as result of our works instead of that which has been imputed into us by grace through faith in Christ Jesus and this grace this grace works in us making his saints, enpowering us to overcome sinful tendencies that once held us captive before believing in Christ.
The person that been set apart as a personal property of the living God is dedicated to him alone ,his/her life is to be lived to the glory of God its owner . 1cor 6:20
The kind of behavior the world expect of those who claim to be followers of Christ is to be radically different in their conduct; lifestyle and even in their expectations , the Bible says Romans12:2
"Don't copy the behavior and customs of this world.....