And Simon Peter answered and said, Thou art the Christ, the Son of the living God. (Matthew 16:16)
Most of Jesus’ earthly ministry centered around the Sea of Galilee, aka the Sea of Tiberius, with His ministry headquarters at Capernaum. The furthest north He traveled, as recorded in the Gospels, was Caesarea Philippi, an ancient Roman city located at the southwestern base of Mount Hermon. Formerly, it carried the name of Paneas in association with the Greek god Pan. Herod the Great erected a white marble (pagan) temple there in honor of Caesar Augustus in 19 BC. Philip II (the Tetrarch) founded the city of Paneas and renamed it Caesarea in honor of Caesar Augustus in 14 AD.
Mount Hermon bears the ignominy of being the frequent site of pagan worship. “In the Book of Enoch, Mount Hermon is the place where the Watcher class of fallen angels descended to Earth. They swear upon the mountain that they would take wives among the daughters of men and take mutual imprecation for their sin (Enoch 6).” From a grotto at the foot of Mount Hermon used to issue a spring that has since stopped due to seismic activity.
“The pagans of Jesus’ day commonly believed that their fertility gods lived in the underworld during the winter and returned to earth each spring. They saw water as a symbol of the underworld and thought that their gods traveled to and from that world through caves. To the pagan mind, then, the cave and spring water at Caesarea Philippi created a gate to the underworld. They believed that their city was literally at the gates of the underworld—the gates of hell. In order to entice the return of their god, Pan, each year, the people of Caesarea Philippi engaged in horrible deeds, including prostitution and sexual interaction between humans and goats.”
It was to this place that Jesus brought His disciples and asked, “Whom do men say that I, the Son of man am?” (Matthew 16:13). The disciples recited the popular rumors: John the Baptist, Elijah, Jeremiah or one of the prophets. Then, “He saith unto them, But whom say ye that I am?” (Matthew 16:15). Without hesitation, “Simon Peter answered and said, Thou art the Christ, the Son of the living God” (Matthew 16:16). “And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven. And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it” (Matthew 16:17-18, emphasis mine).
Jesus then disclosed details of His coming crucifixion. “Then Peter took him, and began to rebuke him, saying, Be it far from thee, Lord: this shall not be unto thee” (Matthew 16:22). Jesus, in turn, rebuked Peter in the harshest of terms. “Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men” (Matthew 16:23, emphasis mine). Then to all Jesus counted the cost of discipleship. “If any man will come after me, let him deny himself, and take up his cross, and follow me. For whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it” (Matthew 16:24-25, emphasis mine). He closed the discussion with these words. “For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works. Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom. (Matthew 16:27-28, emphasis mine).
“And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart, (Matthew 17:1, emphasis mine). The summit of Mount Hermon is 9,232 ft. (almost two miles) above sea level. From the “gates of hell” to the portal of the Watchers, Jesus ascended with His closest disciples; “And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light. And, behold, there appeared unto them Moses and Elias talking with him” (Matthew 17:2-3.) The disciples were flabbergasted. They did not know how to respond or react to what they were witnessing. “Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias” (Matthew 17:4, emphasis mine). Perhaps because the mountain was littered with all kinds of shrines to pagan gods,
Peter thought it would be appropriate to build something similar for Jesus, Moses, and Elijah. A voice from heaven quickly put the kibosh on that idea.
“While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him” (Matthew 17:5).
Gates are defensive barriers designed to keep out the enemy. The gates of hell are no different. Satan is at war against the Kingdom of God, and he erects all kinds of barriers to keep the Kingdom of God from the hearts of those who are perishing. Peter confessed, “Thou art the Christ, the Son of the living God” (Matthew 16:16). Upon that confession – that “rock” – Jesus declared, “I will build my church; and the gates of hell shall not prevail against it” (Matthew 16:18). All that they had witnessed would not be clear until after Jesus’ resurrection and ascension. Peter later recalled, “… [we] were eyewitnesses of his majesty. For he received from God the Father honour and glory, when there came such a voice to him from the excellent glory, This is my beloved Son, in whom I am well pleased. And this voice which came from heaven we heard, when we were with him in the holy mount. (2 Peter 1:16-18, emphasis mine).
On the mountain, Jesus received His marching orders, and it was time to storm the gates of hell. Luke records “And it came to pass, when the time was come that he should be received up, he stedfastly set his face to go to Jerusalem” (Luke 9:51, emphasis mine). Jesus tore down the gates with His death, but more so with His resurrection. The gates of hell cannot stop His Church, and we have our orders: “ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth” (Acts 1:8). “And Jesus came and touched them, and said, Arise, and be not afraid” (Matthew 17:7, emphasis mine).
 Temples of Mount Hermon – https://en.wikipedia.org/wiki/Temples_of_Mount_Hermon
 Ray Vander Laan, That the World May Know, “The Gates of Hell” – https://www.thattheworldmayknow.com/gates-of-hell-article