Part III, Article VII. Of the Keys.
1] The keys are an office and power given by Christ to the Church for binding and loosing sin, not only the gross and well-known sins, but also the subtle, hidden, which are known only to God, as it is written in Ps. 19:13: Who can understand his errors? And in Rom. 7:25 St. Paul himself complains that with the flesh he serves the law of sin. 2] For it is not in our power, but belongs to God alone, to judge which, how great, and how many the sins are, as it is written in Ps. 143:2: Enter not into judgment with Thy servant; for in Thy sight shall no man living be justified. 3] And Paul says, 1 Cor. 4:4: For I know nothing by myself; yet am I not hereby justified.
The Office of the Keys are the power given to the Church to bind and loose sins (Matthew 16:13-20). The first key is the key of binding which holds the unrepentant sinner in his sins and just condemnation. The second key is the key of loosing, which frees the repentant sinner from his sin and grants him forgiveness for Christ’s sake. Pastors exercise this office on behalf o the Church for the sake of the Gospel and the comfort of consciences. The Office of the Keys should be applied to both known sin and unknown sin. Even if we do not know all our sins the Office of the Keys can be applied regardless as God knows them and forgives them (Psalm 19, Romans 7).
We should not judge how great or how many sins are. This belongs to God alone. Rather we should forgive sins and condemn open sin. Where appropriate we should use the binding key of excommunication, but always be standing ready the use the loosing key of forgiveness. We should use God’s Word to judge, not judge based on ourselves lest we get haughty, or think one person a worse man than another. We are all sinners. Thus we in the Church can rightly condemn sin and judge it, but always with the view that we are sinners in need of salvation. The Gospel must always be close at hand, for that is the true power of the Keys. We will talk much more about the Office of the Keys in the Treatise on the Power and Primacy of the Pope (Psalm 143, 1 Corinthians 4).
1 The day is surely drawing near
When Jesus, God’s anointed,
In all His power shall appear
As judge whom God appointed.
Then fright shall banish idle mirth,
And flames on flames shall ravage earth
As Scripture long has warned us.2 The final trumpet then shall sound
And all the earth be shaken,
And all who rest beneath the ground
Shall from their sleep awaken.
But all who live will in that hour,
By God’s almighty, boundless pow’r,
Be changed at His commanding.3 The books are opened then to all,
A record truly telling
What each has done, both great and small,
When he on earth was dwelling,
And ev’ry heart be clearly seen,
And all be known as they have been
In thoughts and words and actions.4 Then woe to those who scorned the Lord
And sought but carnal pleasures,
Who here despised His precious Word
And loved their earthly treasures!
With shame and trembling they will stand
And at the judge’s stern command
To Satan be delivered.5 My Savior paid the debt I owe
And for my sin was smitten;
Within the Book of Life I know
My name has now been written.
I will not doubt, for I am free,
And Satan cannot threaten me;
There is no condemnation!6 May Christ our intercessor be
And through His blood and merit
Read from His book that we are free
With all who life inherit.
Then we shall see Him face to face,
With all His saints in that blest place
Which He has purchased for us.7 O Jesus Christ, do not delay,
But hasten our salvation;
We often tremble on our way
In fear and tribulation.
O hear and grant our fervent plea;
Come, mighty judge, and make us free
From death and ev’ry evil.(LSB 508)