Hebrews 5:14 is a verse with a lot of insight: “But solid food is for the mature, who because of practice have their senses trained to discern good and evil.” This tells us something about spiritual maturity:

— the spiritually mature person consumes “solid food” and not just “milk” (:13)
— the spiritually mature person did not become that way overnight; they got it “because of practice.”
— the “practice” the mature person has engaged in is that they have “trained their senses to discern good and evil.” So good and evil (courses, teachings) are not always evident; it takes “practice” to learn to discern.

Remember this is in the context of the writer explaining to his readers about the superior priesthood of Christ, which they were not understanding, and he upbraids them for the practice of consuming only milk and not solid food.

This should challenge many of us today. We should not be discouraged if we are not spiritually mature overnight — it does take time and practice to grow to maturity. But on the other hand, we SHOULD be dismayed if over time we have not learned discernment and insight. We must commit ourselves to the daily disciplines of Bible reading, study, and application to life, which will give us the “practice” to “train our senses” to discern good and evil in what is being taught, as well as for our own direction for life.