The scriptures are clear that each of us should be continuously expanding our knowledge. Here are a few examples
36. The glory of God is intelligence, or, in other words, light and truth. D&C 93:36
7. And as all have not faith, seek ye diligently and teach one another words of wisdom; yea, seek ye out of the best books words of wisdom, seek learning even by study and also by faith; D&C 109:7
19. And if a person gains more knowledge and intelligence in this life through his diligence and obedience than another, he will have so much the advantage in the world to come. D&C 130:19
28. He that keepeth his commandments receiveth truthand light, until he is glorified in truth and knoweth all things.
29. Man was also in the beginning with God. Intelligence, or the light of truth, was not created or made, neither indeed can be.
30. All truth is independent in that sphere in which God has placed it, to act for itself, as all intelligence also; otherwise there is no existence. D&C 93:28-30
It is the act of continually seeking greater light and knowledge that caused the restoration of the gospel. Think about this statement by Joseph Smith: “...for how to act I did not know, and unless I could get more wisdom than I then had, I would never know…” JS-History 1:12
Likewise, we receive greater light when we seek greater light. Wisdom is added to wisdom and we receive greater wisdom as we seek it. (Reference Alma 12:9-11).
There are many versions of the quote listed below because many have re-quoted it in different ways. Here is the earliest reference to this idea that I was able to find.
"Who can see the barely perceptible line between the man who can not read at all and the man who does not read at all? The literate who can, but does not, read, and the illiterate who neither does nor can?" The Southern Workman, Volume 39, Number 7 page 384, Comment by Joseph D. Eggleston, Jr. state superintendent of public instruction in Virginia.
Harry Truman said, “Not all readers are leaders, but all leaders are readers"
Without seeking to learn and understand leadership you cannot improve your leadership. You will stagnate and eventually your skill will deteriorate until you become ineffective. When we read and study we expand our knowledge and improve our leadership. It is this act of continually learning that enables us to more effectively employ the 5 leadership principles.