176. Behold, I have set before thee an open door, signifies that heaven is open to those who are in truths from good from the Lord. That by "an open door" is signified admission, is evident. The door is said to be open to those who are of the church in Philadelphia, because by that church are meant those who are in truths from good from the Lord, and to them the Lord opens heaven. But on this subject something not before known shall be declared. The Lord alone is the God of heaven and earth (Matt. 28:18); they therefore who do not directly approach Him, cannot see the way to heaven, nor can they find the door, and if haply they are permitted to approach it, it is shut, and if they knock it is not opened. In the spiritual world there are actually ways which lead to heaven, and there are here and there gates, and they who are led to heaven by the Lord, take the ways which lead thither, and enter through the gates. That there are ways there, may be seen in the work concerning Heaven and Hell (n. 479, 534, 590); and also gates (n. 429-430, 583-584). For all things which are seen in the heavens are correspondences, thus also, ways and gates; for ways correspond to truths, and thence signify them, and gates correspond to admission, and thence signify it.
 Since the Lord alone leads man to heaven, and opens the door, therefore He calls Himself "the way" and also "the door": "the way" in John:
I am the way, the truth, and the life (John 14:6).
The door in the same Evangelist:
I am the door of the sheep, by Me, if any man enter in, he shall be saved (John 10:9).
Since there are both ways and doors in the spiritual world, and angelic spirits actually go in those ways, and enter into heaven by doors, therefore "doors," "gates," and "portals" are frequently mentioned in the Word, by which is signified entrance; as in these places:
Lift up your heads, O ye gates, lift them up, ye doors of the world, and the King of Glory shall come in (Ps. 24:7, 9).
Open ye the gates, that the just nation, which doeth fidelity, may enter in (Isa. 26:2).
The five prudent virgins went in to the wedding, and the door was shut; and the five foolish virgins came and knocked, but it was not opened (Matt. 25:10-12).
Jesus said, Strive to enter in at the straight gate, for many will seek to enter in, and shall not be able (Luke 13:24; besides others).
Since "a door" signifies entrance, and "the New Jerusalem" signifies the church consisting of those who are in truths from good from the Lord, therefore the New Jerusalem is described also as to "its gates, upon which there were angels," and it is said, They should not be shut (Rev. 21:12-13, 25).