In the Pirates of the Caribbean movie Jack Sparrow (one of the main characters) asks his crew: “What do the keys do?”. He gets back a very simple answer he was not looking for – “the keys open things?”
In Matthew 16:19, Yeshua tells his disciple Peter that he will be given the keys of the kingdom of heaven. They would enable him to “bind” (or forbid) and “loose” (or permit) things on earth and it would be done in heaven as well.
“I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.” (Matt. 16:19 NIV)
Behind the Judeo-Greek text is a Hebrew concept of the מַפְתְּחוֹת מַלְכוּת הַשָׁמָיִם (maftechot malchut hashamaim) – “keys of the kingdom of heaven”. What do these keys do? In this case “a key” מַפְתֵּחַ (mafteach) is a tool that opens the door into God’s domain. In Hebrew פֶּתַח (petach) is “an opening”. In Mishna, פְּתִיחָה (peticha) is “an introduction” (also an opening of something that follows). Both words come from the verb “to open” פָּתַח (patach). For contrast, the Hebrew verb “to close” is סָגַר (sagar) and to “lock” or “fasten” is נָעַל (naal). Neither word is related to the idea of a key in Hebrew, because the primary purpose of “a key” מַפְתֵּחַ (mafteach) is not to lock, but “to open” פָּתַח (patach).