2 Ne. 31:2 Wherefore, the things which I have written sufficeth me, save it be a few words which I must speak concerning the doctrine of Christ; wherefore, I shall speak unto you plainly, according to the plainness of my prophesying.When God works among his children he works after the manner of plainness. During Jesus' mortal ministry he often taught in parables. When his apostles asked him why he taught that way, he explained1 that it was so that the faithful could understand, while the faithless would not be able to. But how can we say that God works after the manner of plainness if he teaches in a way to intentionally obfuscate the doctrine to the understanding of some?
3 For my soul delighteth in plainness; for after this manner doth the Lord God work among the children of men. For the Lord God giveth light unto the understanding; for he speaketh unto men according to their language, unto their understanding.
D&C 84:45 For the word of the Lord is truth, and whatsoever is truth is light, and whatsoever is light is Spirit, even the Spirit of Jesus Christ.In other words, our own obedience and diligence affect just how "plain" the word will seem to us. This is not because the nature of the teaching has changed, rather we have allowed our eyes to be opened by the Spirit until the teachings become increasingly plain to our understanding. I just love what verse 52 says: "And whoso receiveth not my voice is not acquanted with my voice." Could it be any more plain?
46 And the Spirit giveth light to every man that cometh into the world; and the Spirit enlighteneth every man through the world, that hearkeneth to the voice of the Spirit.
D&C 84:52 And whoso receiveth not my voice is not acquainted with my voice, and is not of me.
D&C 84:54 And your minds in times past have been darkened because of unbelief, and because you have treated lightly the things you have received—
1. Matthew 13:10-17