I would agree with the poet's didactic message. The poem "If" is a poem that teaches through illustrations. The speaker is teaching his son what it takes to become a man and inherit the earth in all its fullness. If you can balance your life with self confidence but not too much self confidence, you are on your way to becoming a man. The poem is instructing the son to be patient. The poem is instructing the son to Keep his head "when all about you/ Are losing theirs and blaming it on you."
Every stanza requires a balanced life.
If you can wait and not be tired by waiting,
Or, being lied about, don't deal in lies,
Or being hated don't give way to hating,
And yet don't look too good, nor talk too wise;
No doubt, self control is one key concept that the speaker is relating to his son. Don't hate. Don;t give way to hating. Live a balanced life that will help you become a man.
Dream, but don't make dreams your master. If you can lose it all and begin all over again and never say a word about your losses, you are learning to become a man:
If you can make one heap of all your winnings
And risk it on one turn of pitch-and-toss,
And lose, and start again at your beginnings,
And never breathe a word about your loss:
If you can hold on when everything in your body is screaming give up, you will become a man. Endurance is the key to becoming a man. Never, ever, give up:
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"
Truly, this poem is filled with valuable instruction. It is the key to becoming a man. If you can remain humble and yet have the confidence to interact with royalty, then you are on your way to becoming a man. If you can keep foes and friends from hurting you, you are becoming a man:
If you can talk with crowds and keep your virtue,
Or walk with Kings---nor lose the common touch,
If neither foes nor loving friends can hurt you,
If all men count with you, but none too much:
If you can fill the unforgiving minute
With sixty seconds' worth of distance run,
Yours is the Earth and everything that's in it,
And---which is more---you'll be a Man, my son!