ChristianAnswers.Net WebBible Encyclopedia
Keys are frequently mentioned in Scripture. It is called in Hebrew maphteah, i.e., the opener (Judg. 3:25); and in the Greek New Testament kleis, from its use in shutting (Matt. 16:19; Luke 11:52; Rev. 1:18, etc.).
Christ: “And I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” —Matthew 16:19 NKJV (compare Matt. 18:18)
Figures of ancient Egyptian keys are frequently found on the monuments, also of Assyrian locks and keys of wood, and of a large size.
Referring to Eliakim the son of Hilkiah, the Lord God of hosts said,
“Then I will set the key of the house of David on his shoulder, When he opens no one will shut, When he shuts no one will open.” —Isaiah 22:22 NASB
In the above verse, the word key is used figuratively of power or authority or office, as it is in…
“And to the angel of the church in Philadelphia write, ‘These things says He who is holy, He who is true, “He who has the key of David, He who opens and no one shuts, and shuts and no one opens” —Rev. 3:7 NKJV
Then the fifth angel sounded: And I saw a star fallen from heaven to the earth. To him was given the key to the bottomless pit. —Rev. 9:1 NKJV
Then I saw an angel coming down from heaven, having the key to the bottomless pit and a great chain in his hand. —Rev. 20:1 NKJV
The “key of knowledge” (Luke 11:52; compare Matt. 23:13) is the means of attaining the knowledge regarding the kingdom of God.
Christ: “Woe to you lawyers! For you have taken away the key of knowledge; you yourselves did not enter, and you hindered those who were entering.” —Luke 11:52 NASB
The “power of the keys” is a phrase in general use to denote the extent of ecclesiastical authority.