In "If," a poem about the kind of moral courage and wisdom it takes to become a man, Kipling uses personification several times. Personification is attributing human qualities to something non-human, such as an animal, an inanimate object, or an abstract concept. In the poem's third stanza, Kipling uses personification to describe an abstract quality. He says:
"If you can dream and not make dreams your master ..."
A dream is abstract, an unrealized wish or desire, but here the poet speaks of it as a "master." A master is a human, someone who is in charge and tells others what to do. By understanding that a dream can become like a human being in controlling you and ordering you around, even causing you pain, as school masters were allowed to do in Kipling's day, Kipling makes it easier to understand the danger that a dream or desire can pose. You cannot become fully a "man"--today, we would probably say human being--that is to say, someone in charge of your own destiny, if you allow your dreams to control you.