Matthew 16:18
16 Simon Peter answered, “You are the Christ, the Son of the living God.” 17 And Jesus answered him, “You are blessed, Simon son of Jonah, because flesh and blood did not reveal this to you, but my Father in heaven! 18 And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overpower it. 19 I will give you the keys of the kingdom of heaven. Whatever you bind on earth will have been bound in heaven, and whatever you release on earth will have been released in heaven.” 20 Then he instructed his disciples not to tell anyone that he was the Christ.
2 Enoch 42:1
Secrets of Enoch1 I saw the key-holders and guards of hell's gates, standing like great serpents, with faces like extinguished lamps, fiery eyes, and sharp teeth. I observed all the Lord's works, recognizing their righteousness, while human works vary, some good and others bad. Through their deeds, those who act wickedly are known.
Notes and References
"... The means by which the apocalyptic seer descends to the underworld are not usually specified more closely than by saying that an angel took him or her. Although medieval Jewish texts refer to specific entrances to the underworld, as in Greek tradition,59 these are not used in the tours of hell, nor is there often any reference to obstacles to be passed. Enoch shudders at the sight of the gatekeepers of hell (2 Enoch 42: I). Ezra passes without difficulty, like the righteous dead, the two fiery lions who guard the gates of hell (VisEzra 3). Paul, like Odysseus, has to cross the river Oceanus to reach hell in the far west, but it is not said how he does so (Apocalypse of Paul 31). In the Gedulat Moshe, the fire withdraws before Moses as he enters hell, but when he fears to descend to the abyss of fire and snow, the Shekinah goes before him to protect him from the angels of punishment. The angelic guides (or, in the case of Joshua ben Levi, the prophet Elijah, and, in the apocalypses of the Virgin, Christ himself) are a constant feature of the tours: they lead, guide, explain and answer questions ..."
Bauckham, Richard The Fate of the Dead: Studies on the Jewish and Christian Apocalypses (p. 36) Brill, 1998