What does Revelation 3:7 mean?
Philadelphia was located about 28 miles southeast of Sardis. Its name combines the Greek words for "love" and "brothers." The city was known for its numerous vineyards. The abundant production of wine led the citizens into the worship of Dionysius, the god of wine. The city was also prone to earthquakes. The king of Pergamum founded the city in in 189 BC and named it Philadelphia because of His brother's loyalty to him; his brother was the king of Lydia.In His letter to the church at Philadelphia Jesus identifies himself as holy and true. The two characteristics are significant. Because Jesus is holy, He cannot lie. Therefore, He is both holy and true. Hebrews 7 tells how Jesus is a better priest than the priests of Israel. Verse 26 describes Him as "a high priest, holy, innocent, unstained, separated from sinners, and exalted above the heavens." In John 14:6, Jesus identified Himself to His disciples as the truth. The church at Philadelphia could accept Jesus' words as absolutely true.
Jesus also identifies himself in verse 7 as the one who has the key of David. The mention of David puts this verse in a messianic context. Someday Jesus will exercise His authority to allow saved individuals, both born-again Gentiles and saved Jews to enter His earthly kingdom. Also, He will use the key to lock out all unbelievers. Because Jesus is the son of David, He has the indisputable right to the royal line. As Israel's promised king, He will rule the nations from the throne of Israel.
It is also true that Jesus holds the key to open and shut a door that no one can open. He was able to use the key to open the doors of opportunity for the church at Philadelphia to advance the gospel into Asia's unevangelized regions. Further, He could use the key to lock out the church's enemies.