Beleivers in Christ are Saints
We say that the real saints of Christ must be good, stout sinner and remain saints who are not ashamed to pray the Lord's Prayer...They are not called saints because they are without sin or have become saintly through works. On the contrary, they themselves, with all their works, are nothing but condemned siners. But they become holy through a foreign holiness, namely, through that of the Lord Jesus Christ, which is given them by faith and thus becomes their own.
What Luther Says - #3978 - p. 1247