Rudyard Kipling's famous poem "If" is essentially an instruction manual written to his son on how to become a "man." In the second stanza of the poem, the speaker encourages his son to treat "triumph and disaster" the same. The speaker is essentially commenting on the importance of maintaining composure and remaining stoic during victories and defeats. If one were to suddenly lose something or someone, the speaker believes that a "man" should accept the loss with dignity.
In the third stanza, the speaker comments on how a person should react to an unexpected loss by simply accepting the loss and starting their specific endeavor from the beginning without ever speaking about the aforementioned loss. The speaker is a proponent of fortitude, persistence, and hard work. According to the speaker, a "man" will learn from his losses and not dwell on his failures. Instead of quitting, a person should accept their loss and start their project from the beginning with a new, fresh outlook. The speaker also encourages his son to not speak about his loss or failures. Instead, he encourages the boy to maintain a positive attitude and restart from the beginning without commenting on his past failures.