SIKHISM: Master thyself to conquer universe

The Guru Granth Sahib said:
Whatever the Lord does, He does all by Himself.
In an instant, He establishes, and destroys.
I asked my teacher how can this Universe be established, or destroyed in an instant, when it takes months to even build a single house.
My teacher said that time and its measurement has a different meaning for each piece of existence. For a planet, one lifetime has a different meaning than for a human being. And all human beings do not achieve equally within the same life period. The achievements of some stand head and shoulders above their colleagues. Even within the same person, time has a different meaning on different days. When children are playing, the same one hour is too short, but is never ending in school when faced with a subject they may not like. I could understand the examples, but I still could not grasp the concept my teacher was teaching me. He laughed, and asked me to come back tomorrow morning after I had a good sleep. When I returned in the morning, he was eagerly waiting for me. “Tell me about your dreams,” he said. I said I had a wonderful time with my friends. In my dream, they came to my house, and we went to the cinema. We watched a movie, and then, a friend took us to the airport. His father was with the air force, and he took us for a long flight, and I could see Mount Everest. I had felt very close to the stars, as we flew very high for many days.
“And all that in just one night? What happened to Time?” he smiled. Tapping my head, he said, “Your Universe is here. Master yourself, and make it the way you want.”
Guru Granth Sahib says:
Those who conquer their own mind, by Teacher’s Grace,
They conquer the Universe.