Genuine Truth in the Literal Sense of the Word, which the Truth of Doctrine must be, appears only to those who are in Enlightenment from the Lord

Enlightenment is from the Lord alone, and is with those who love truths because they are truths, and apply them to the uses of life; with others there is no enlightenment in the Word. That enlightenment is from the Lord alone is because the Word is from Him, and therefore He is in it; that it is with those who love truths because they are truths and apply them to the uses of life, is because they are in the Lord and the Lord is in them. For the Lord is the Truth itself; and the Lord is loved when man lives according to His Divine truths; thus when uses are performed from them,—according to these words in John: “In that day ye shall know that … ye are in Me, and I in you. He that hath My commandments, and doeth them, he it is that loveth Me; … and I will love Him, and will manifest Myself to him; … and I will come unto him, and make an abode with him” (xiv. 20, 21, 23). These are they who are in enlightenment when they read the Word, and to whom the Word is bright and translucent. The reason why the Word to them is bright and translucent is that in the least parts of the Word there is a spiritual and a celestial sense, and these senses are in the light of heaven; and therefore through these senses and their light the Lord flows in into the natural sense of the Word, and into the light of this with man. Hence, from an interior perception, man acknow­ledges the truth, and then sees it in his thought; and this as often as he is in the affection of truth for the sake of truth. For perception comes from affection, and thought from perception; and thus the acknowledgment is produced which is called faith. (TCR n. 231)

Since few know how it is with the influx of Divine truth, and enlightenment thence with man, it is permitted here to say something on these subjects. It is known in the church that the good of love and the truth of faith is all not from man, but is with him out of heaven, from the Divine there; and that they are in enlightenment who receive this. But the influx and enlightenment are effected in this manner: Man is such that as to his interiors, which are of the thought and will, he can look down­wards and can look upwards. To look downwards is to look out­wards, into the world and to himself; and to look upwards is to look inwards, to heaven and to God. Man looks outwards, which is called downwards, of himself; since when he looks of himself he looks to hell. But man looks inwards not of himself but of the Lord; this is called upwards because as to his interiors which are of the will and the understanding he is then elevated by the Lord to heaven, and so to the Lord. The interiors are in fact actually elevated; and then are actually withdrawn from the body and from the world. When this is effected the interiors of man actually come into heaven, and into its light and heat. Hence he receives influx and enlightenment; the light of heaven illuminates his understanding,—for that light is Divine truth, which proceeds from the Lord as a sun; and the heat of heaven enkindles his will,—for that heat is the good of love, which at the same time proceeds from the Lord as a sun. As man is then among the angels there is communicated to him from them, that is through them from the Lord, the intelligence of truth and the affection of good. It is this communication which is called influx and enlightenment. But it should be known that influx and enlightenment are effected according to the faculty of reception in man; and the faculty of reception is according to his love of truth and of good. They therefore are elevated who are in the love of truth and of good for the sake of truth and good, as ends. (AC n.10,330)