“congregation.” This is the translation of the word commonly translated “Church,” ekklēsia (#1577 ἐκκλησία). Ekklēsia has a wide range of meanings, but none of them refer to a physical building. The word ekklēsia refers to an assembly of people, any assembly of people for any reason. It does not have to be a religious gathering. The gathering of people in Acts 19:32 was a mob coming together with no particular ethnic or religious affiliation, in fact, the Bible says, “most of them did not know why they had come together” (ESV). In Acts 7:38 the term is used of the Jewish throng, including some Gentiles (Exod. 12:38), who were led out of Egypt by Moses. Another example is Matthew 18:17, where the “congregation” could refer to a congregation of Jews or the Church. In that verse, “congregation” has a multidispensational application. So the term ekklēsia does not solely apply to the Christian Church.
In modern English the term “Church” refers to a Christian building of worship; however this is not how the word ekklēsia is used in Scripture. Translating ekklēsia as “Church” causes some problems, primarily because almost everyone who reads “Church” thinks of the Christian Church. But, as we have seen, ekklēsia does not always refer to Christians.
We do need to recognize that the most common use of ekklēsia is referring to Christians, but as a congregation of people, not as a “church” building. This is made clear in Colossians 1:18: Christ is “the head of the body, the church,” which refers to the entire world congregation of Christians (Cp. also: Acts 5:11). The term ekklēsia can be used solely of a particular local assembly of believers (e.g., 3 John 1:10), or to specific groups, which by extension applies to the entire Church (e.g., 1 Cor. 1:2; 2 Cor. 1:1; Gal. 1:2; Eph. 1:22). Lastly, ekklēsia is used in Revelation (2:1, etc.) in regard to the “congregation” after the Rapture. These are Jews and some God-fearing Gentiles, but not Christians, who have been Raptured off the earth before the book of Revelation starts (see commentary on Revelation 2:1).
“gates of the grave.” This was a Semitic idiom for death. The word-picture being painted was that when a person died, he entered the world of death (sheol = “gravedom,” the state of being dead) and the gates were shut behind him and he could not get back to the world of life. For the Hebrews who correctly believed that when a person died he was actually dead and not alive in any form, the “gates of the grave” were a picture of the permanence of death, and the only way to re-enter life was by resurrection. However, most cultures in the ancient world believed in some form of life after death, and in some of those cultures in the Middle East, dying was thought of as going through a gate or even a series of gates. The NIV Study Bible (1984 edition) text note on Job 17:16 says: “In Mesopotamian literature, all who entered the netherworld passed through a series of seven gates.”
Sheol was the Hebrew word for the state of being dead (not the physical place of the dead, which was the grave). People who were dead were said to be “in sheol,” in the state of death. The Old Testament refers to the gates of sheol (Job 17:16; Isa. 38:10), and the “gates of death” (Job 38:17; Ps. 9:13; 107:18), and other literature of the time period does too, such as the Apocrypha. In Matthew 16:18, Jesus is speaking of building his “congregation,” which will consist of saved people from Israel and Gentiles, and he knows that some will be alive when he comes and some will be dead, so he makes the point of saying that the “gates of the grave will not prevail against it.” Jesus knew the reason that the gates of the grave would not overcome his congregation was that he would raise those who were dead back to life; the gates of the grave would open and the dead would come out. The Old Testament and Gospels have a number of clear verses about the dead being raised, including Job 19:25; Isaiah 26:19; Ezekiel 37:12-14; Daniel 12:2, 13; Hosea 13:14; and John 5:28, 29;
The righteous people who have died will be raised in one of the resurrections (while dead Christians will be raised in the Rapture (1 Thess. 4:13-17)). Dead people who are resurrected in the “first resurrection” (Rev. 20:5, 6), also called the “Resurrection of the Righteous” (Luke 14:14; Acts 24:15), and “the resurrection of life” (John 5:29), will be part of the Messianic Kingdom on earth and live forever with Jesus. [For more on the Rapture and the resurrections, see commentary on Acts 24:15].
There are some commentators who historically have made “death” figurative for the powers of death or evil that cause death and so the way the phrase “gates of hell” is generally used in Christendom is that it means that demons and the powers of the Devil (“hell”) will not overcome the Church. However, although it is true that demons will not overcome the Church, that is not what the verse is saying. Jesus was not making the point that the Devil would not be able to overcome the Church, he was making the point that death could not defeat his Church.