By President David O. McKay
 And I give unto you a commandment that you shall teach one another the doctrine of the kingdom.
Teach ye diligently and my grace shall attend you, that you may be instructed more perfectly in theory, in principle, in doctrine, in the law of the gospel, in all things that pertain unto the kingdom of God, that are expedient for you to understand;
Of things both in heaven and in the earth, and under the earth; things which have been, things which are, things which must shortly come to pass; things which are at home, things which are abroad; the wars and the perplexities of the nations, and the judgments which are on the land; and a knowledge also of countries and of kingdoms—
That ye may be prepared in all things when I shall send you again to magnify the calling where unto I have called you, and the mission with which I have commissioned you.
—Doctrine and Covenants 88:77–80.
Can you get, in all literature, a more comprehensive statement of the field into which teachers must enter for the purpose of being prepared to teach the word of God than in that revelation?
To Help or To Hinder
In a thoughtful work entitled, "The Religion Worth Having," Thomas Nixon Carver once gave several sociological marks of what he considered the true church. Among other things, I find this comparison:
Everyone is familiar with the intense struggle for existence that is carried on among the trees of the forest. It is asserted that the struggle is so intense and the issue of life and death so sharply drawn among the young pines of a thicket, that the cutting of an inch from the top of one of them will doom it to ultimate extinction. Even that slight difference puts it at a disadvantage, and it never regains what was lost, but falls farther and farther behind and eventually is killed by its less unfortunate rivals.
Now let us imagine that these trees were conscious beings and capable of having a religion. Let us suppose further that one set of trees possessed a religion which stimulated growth and helped them in the struggle for soil and light, while another possessed a religion which retarded growth and hindered in the struggle. Is there any doubt as to which of these religions would ultimately dominate the forest? Those trees which happen to possess the religion which helped them would survive, and those which happen to possess the kind of religion which hinders them would perish; and their religion would perish with them.
The issue of life and death is never so sharply drawn among human beings as among the trees of the forest, but in the long run the result appears to be very much the same; if that be true, it will follow that the religion which best fits men for the struggle with the forces of the world, which enables them to survive in this struggle, will eventually be left in possession of the world.
The Superiority of a Divine Organization
I am grateful for membership in a Church whose religion fits men for the struggle with the forces of the world and which enables them to survive in this struggle. One of these acting forces is the responsibility of teaching and the opportunity afforded in this Church for so many to share this responsibility.
There are others, also; for example, much might be said about the accomplishment of the Church in enabling men to win domination over the forces of nature; in other words, efficiency in helping supply the material needs of mankind. Though this phase of our religion is glorious to contemplate and will establish in the minds of thinking men the superiority of this divine organization, I shall merely mention it as one of the many commendable features  which help to fit us in the struggle with nature's forces.
Neither shall I dwell upon the social efficiency except to suggest that anyone who will give thought to it, and examine the divine organization and the opportunity that we have for influencing for good our young people as social beings, will be convinced of the efficacy and superiority of the Church in this regard.
An Army of Teachers
But I should like now particularly to draw attention to the teaching force of the Church.
Martin Luther once said, "Count it one of the highest virtues upon earth to educate faithfully the children of others which so few, and scarcely any, do their own."
The obligation of teaching is placed by the Church first upon the parents, and the responsibility thereof has been placed upon them by divine command. But besides parents there are tens of thousands of men and women, and boys and girls, who have accepted the responsibility of teaching. In the priesthood quorums alone the number runs into many thousands. And if we add mothers and fathers and young men and young women in the Relief Society, the Sunday School, the Mutual Improvement Association, the Primary, and the seminaries, we have an army of teachers who have the privilege and responsibility of exercising what Luther calls "one of the highest virtues upon the earth."
Attributes of the True Teacher
Now in furnishing opportunity for so many to get the development that comes to the true teacher, think what the Church is doing to help this army of teachers as individuals to become strong in the battle against the forces of the world!
First, it places upon them the obligation of teaching their fellowmen by example; and there is no better safeguard placed upon an honest man or a sincere woman.
Second, it develops the divine attribute of love for others. Jesus asked one of His apostles, "Simon, son of Jonas, lovest thou me more than these?...Yea, Lord; thou knowest that I love thee....Feed my lambs." (John 21:15.) Love should precede the responsibility of feeding those lambs. And these tens of thousands of teachers must have in their hearts the love of teaching, the love of their fellowmen, and a willingness to accept this responsibility with the divine attribute of love.
Then there is a third requirement, namely, purity of life. I cannot imagine one who has soiled himself successfully teaching purity to boys. I cannot imagine one who has doubt in his mind about the existence of God impressively teaching this existence of a Deity to young boys and girls. He cannot do it. If he acts the hypocrite and attempts so to teach, what he is will speak louder than what he says—and that is the danger of having doubting men as teachers of your children. The poison sinks in, and unconsciously they become sick in spirit, because of the poison which the person in whom they have confidence has insidiously instilled into their souls. The thought of teachers attempting to teach youth faith in God, when they haven't it, is irreconcilable with consistency, if not indeed unthinkable. So the third qualification is purity of life and faith in the gospel of Jesus Christ.
Finally, it gives them an opportunity to serve their fellowmen, and therein magnify the calling which has come to them, and indeed prove that they are real disciples of Christ. "Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me." (Matthew 25:40). Thus the divine principle of service is instilled in their hearts.
The Responsibility of a Teacher
I ask you to think of the effect upon society, if every worthy teacher, every one, will succeed in influencing only one other to love, to have that same purity of life, and that same desire to serve his fellowmen as he has!
I once observed a young girl in her teens put forth a special effort to speak to the little boy who was by my side. I could see that she wanted to recognize that boy, and that he was glad when he saw her to return her salutation. After we passed her I said, "Who is she?"
"She is my teacher," he answered.
"What is her name?"
"I don't know what her name is, but, oh, she is a dandy!"
He used an incorrect word, but the significance he gave to the word I knew, and the expression on his face I read, and in my heart I thanked the young girl for the influence she had over that boy. Only in her teens, but what that girl will say to him in his class he will accept as Gospel truth; what she does in her life he will emulate; and that young girl (with untold tens of thousands of other teachers) carries the responsibility, in a measure, of molding that boy's character.
Oh, how mighty is the responsibility of a teacher!
God help our teachers to feel the responsibility that comes to them, and to remember that responsibility is not measured alone by what they say, but by what they do, and by the opportunities that have come to them to know good from evil.
McKay, David O. AThe Teacher. The Instructor (Aug 1967): 297–298.
(derived from his April 1914 conference talk)