1 Corinthians 1:1-9
1 Paul, called to be an apostle of Christ Jesus by the will of God, and our brother Sosthenes,
2 To the church of God in Corinth, to those sanctified in Christ Jesus and called to be his holy people, together with all those everywhere who call on the name of our Lord Jesus Christ—their Lord and ours:
3 Grace and peace to you from God our Father and the Lord Jesus Christ.4 I always thank my God for you because of his grace given you in Christ Jesus. 5 For in him you have been enriched in every way—with all kinds of speech and with all knowledge— 6 God thus confirming our testimony about Christ among you. 7 Therefore you do not lack any spiritual gift as you eagerly wait for our Lord Jesus Christ to be revealed. 8 He will also keep you firm to the end, so that you will be blameless on the day of our Lord Jesus Christ. 9 God is faithful, who has called you into fellowship with his Son, Jesus Christ our Lord.
NIV from biblegateway.com
Many people hold an unbiblical view of sainthood. Their idea of a saint is one who has led such an exemplary life that he or she is venerated by the church, but God's Word presents quite a different picture. The Corinthian church struggled with all sorts of ungodly behaviors, yet Paul describes them as "those who have been sanctified in Christ Jesus, saints by calling" (1 Cor. 1:2).
Sanctify means to set apart from common use to a sacred use. Throughout the Bible, the Lord has sanctified days (such as the Sabbath), places (the tabernacle), things (the arch of the covenant), and people. A saint is simply a person whom God has set apart for His purposes. This means that every believer is a saint.
Before you were saved, your position relative to God was one of enmity (Romans 5:10). But the moment you trusted Jesus Christ as your personal Savior, the Lord changed your position and set you apart for Himself. You were born again and are now his child. He forgave your sins an declared you righteous. A saint is not a perfect person but one who is in a right relationship with the heavenly Father. Although our position of sanctification is not predicated on good behavior, the Lord expects us to live in a manner that honors Him.
Just think - God set you apart for a sacred purpose. That means you are here, not to live as you please but to bring glory to Him. He calls us to live according to our new position in Christ. When we accept this responsibility of sainthood with gratitude, we bring joy to the Father's heart.
Stanley, Charles F. "Qualifications for Sainthood." In Touch: Daily Readings For Devoted Living. April 2016. page 28.