#yeshua said, "To you it has been given to know the secrets of the kingdom of God, but for others they are in parables, so that ‘seeing they may not see, and hearing they may not understand.’"
Luke 8:10

See Deuteronomy 29:29 and "the secret things belong to YHWH our Elohim". Spiritual truths are secret things that belong to YHWH and he reveals them to whom he chooses. We are incapable of full understanding unless God opens our eyes.