One of Martin Luther’s greatest theological insights was that believers in Christ are not perfect saints all the time, rather we are simultaneously saints and sinners. We are 100 percent perfect and sinless through faith in Jesus as our Savior but the sinful nature that has been ours since conception in our mothers’ wombs still clings to us until we die. As Lutherans we do not attempt to explain how this can be we simply confess it since it is clearly taught in Scripture and something that also is confirmed in our everyday lives.
Speaking of Scripture, here is a small nugget of Scripture that confirms the simultaneously saint and sinner approach:
Hebrews 10:14: “For by a single offering he has perfected for all time those who are being sanctified.” (ESV)
By one single offering, that is, Jesus’ death for us on the cross, Jesus has perfected us. Our sins were completely paid for on the cross. We are saints.
But it is also true that we “are being sanctified.” To be sanctified means to be made holy. Because our sinful nature still clings to us we are not completely holy yet. But God’s Holy Spirit, who has been poured into our hearts through the Word of God and the sacraments of Holy Baptism and Holy Communion, helps us constantly strive for holiness by overcoming the sinful nature.