A “key” in the scriptural symbolism is representative of the opening power vested in the one who has been duly authorized to act, just as how we might say today something like, “He holds the key to the situation.” 

Peter was given two “keys” (Matthew 16:19), one of which he used on the day of Pentecost when he “opened” the way for the Jews by preaching the Gospel of Christ and the kingdom (Acts 2:22-36). Three thousand Jews entered in though this opened door (verse 41) on that very day. The second key was used three-and-a-half-years later when Peter opened up the way for the Gentiles to enter into the heavenly kingdom, by preaching the gospel to Cornelius who accepting the message, and believing, became the first Gentile convert to Christianity (Acts 10:44-45). In Revelation 1:18, the glorified Savior is represented as speaking, saying “I am he that liveth, and was dead; and, behold, I am alive for evermore, Amen; and have the keys of hell and death.” The Lord Jesus, by virtue of his death and resurrection, accomplished the redemption of the race of mankind from death and hell, hades, the grave. Because he thus bought the race, he has the “keys,” the opening power, to release all mankind from the great prison house of death and the tomb. As we read concerning the Lord Jesus, “The Spirit of the Lord God is upon me; because the Lord hath anointed me…to proclaim liberty to the captives, and the opening of the prison to them that are bound” Isaiah 61:1.

Additional Resources:
Christian Questions Podcast
Episode #1174: “Did God Make Heaven and Hell Humanity’s Destiny? (Part I)”
Uncovering who goes to heaven and what happens to planet Earth
Preview Video
CQ Rewind Show Notes

Episode #1175: “Did God Make Heaven and Hell Humanity’s Destiny? (Part II)”
Unpacking the true meaning of hell and Judgment Day in Scripture
Preview Video
CQ Rewind Show Notes

Episode #1231: “What if I’m Not Good Enough for Heaven?”
Uncovering the destiny of humanity’s billions who don’t go to heaven
Preview Video
CQ Rewind Show Notes

Special 3-part series: “Is the Hell of Christian Tradition Taught in the Bible?”

For a comprehensive study on hell, download the free PDF: “The Truth About Hell”