κλείς (kleis), [Latin] clavis: keys: Mt16:19, Lk11:52, Mt 23:13, Rev 1:18
Background information:
Greek Hellenism: This term means key, catch, door bolt, solution, collar bone, straight, and rowing bench. Euripides’ Medea states “Themis, goddess of oaths, brought her to Hellas across the sea through the dark salt-water over the briny gateway (straight) of the Black Sea.” Homer’s Iliad 14.168 states “She went her way to her chamber and had fitted strong doors with a secret bolt, that no other god might open.” Homer’s Odyssey 21.241 states, “But to thee, goodly Philoetius, do I give charge to fasten with a bar the gate of the court, and swiftly to cast a cord upon it.
Old Testament: This term means key, opener, and shoulder blade. Keys are used to represent power, authority, and office. I will place the key of the House of David on his shoulder, when he open, no one shall shut, when he shuts, no one shall open (Isa.22:22). So they took the key and opened them, and there was their lord lying on the floor, dead (Jdg.3:25). Then may my arm fall from the shoulder, my forearm be broken at the elbow (Job.31:22).
New Testament: This term means key. Jesus states that He will to Peter the keys to the kingdom of heaven. The keys represent the heavenly authority of the church on earth. The promise of the keys is given to Peter alone. The keys confer binding and loosing on earth and heaven. Binding and loosing confer authoritative teaching, lifting or imposing bans, and excommunicating. Woe is given to the law scholars for obscuring, defying, and denying the true knowledge of the Messiah. This key of knowledge was conferred by a delivery of a key bestowing authority.
Scripture:
“I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.” Mt 16:19
Jesus gives Peter authority to lead His Church. Peter is given authority the authority of loosing (opening) and binding (closing) heaven. Like Eliakim, Peter becomes a prime minister for Jesus’ Church. Then, when the time comes, a successor will follow Peter.
“Woe to you, scholars of the law! You have taken away the key of knowledge. You yourselves did not enter and you stopped those trying to enter.” Lk 11:52
The key represents attaining the knowledge regarding the kingdom of heaven. The key provide the means of access of authority.
Conclusion:
Key, clavicle
Catholics believe that Peter is the first shepherd (pope) of the Church on earth. In order for the Church to continue forward, God provided the mechanism whereby successor have assumed the office of authority of Peter. It is important to note that all the disciple were each given the power to bind and loose. The key of knowledge is both a literal and metaphor symbol of authority and access.