2 Thessalonians 2:13-15

But we should and are [morally] obligated [as debtors] always to give thanks to God for you, believers beloved by the Lord, because God has chosen you from the beginning for salvation through the sanctifying work of the Spirit [that sets you apart for God’s purpose] and by your faith in the truth [of God’s word that leads you to spiritual maturity]. It was to this end that He called you through our gospel [the good news of Jesus’ death, burial, and resurrection], so that you may obtain and share in the glory of our Lord Jesus Christ. So then, brothers and sisters, stand firm and hold [tightly] to the traditions which you were taught, whether by word of mouth or by letter from us.