Joachim Jeremias in an extended passage from
Kittel's Greek standard TDNT --
"...the key of David is now (3:7) the key which Christ has in His hands as the promised shoot of David. This is the key to God's eternal palace. The meaning of the description is that Christ has
unlimited sovereignty over the future world. He alone controls grace and judgment. He decides irrevocably whether a man will have access to the salvation of the last age or whether it will be witheld from him...Materially, then,
the keys of the kingdom of God are not different from the key of David...This is confirmed by the fact that in
Mt. 16:19, as in
Rev. 3:7, Jesus is the One who controls them. But in what sense is the power of the keys given to Peter? ....the handing over of the keys is not just future. It is regarded as taking place now... There are numerous instances to show that in biblical and later Jewish usage handing over the keys implies
full authorisation.
He who has the keys has full authority. Thus,
when Eliakim is given the keys of the palace he is appointed the royal steward (
Is. 22:22, cf.
15). When Jesus is said to hold the keys of death and Hades (
Rev. 1:18) or the key of David (3:7), this means that He is, not the doorkeeper, but the Lord of the world of the dead and the palace of God...Hence handing over the keys implies appointment to
full authority. He who has the keys has on the one side control, e.g., over the council chamber or treasury, cf.
Mt. 13:52, and on the other the power to allow or forbid entry, cf.
Rev. 3:7...
Mt. 23:13 leads us a step further. This passage is particularly important for an understanding of
Mt. 16:19 because it is the only one in the NT which presupposes an image not found elsewhere, namely, that of the keys of the kingdom (royal dominion) of God...
Mt. 23:13 shows us that the scribes of the time of Jesus claimed to possess the power of the keys in respect of this kingdom...They exercised this by declaring the will of God in Holy Scripture in the form of preaching, teaching and judging. Thereby they opened up for the congregation a way into this kingdom...by acting as spiritual leaders of the congregation....
As Lord of the Messianic community He thus transferred the keys of God's royal dominion, i.e. the full authority of proclamation, to Peter...In Rabb. lit. binding and loosing are almost always used in respect of halakhic decisions...The scribe binds (declares to be forbidden) and looses (declares to be permitted)...In
Mt. 16:19, then, we are to regard the authority to bind and to loose as
judicial. It is the authority to pronounce judgment on unbelievers and to promise forgiveness to believers." (Jeremias from Kittel/Bromiley,
Theological Dictionary of the New Testament, volume 3, page 748-751)
