From Volume 8 of The Complete Works of Swami Vivekananda, chapter -III, ‘Notes Of Class Talks And Lectures’

I never take much notice of these things. I have come to deal with principles. I have only to preach that God comes again and again, and that He came in India as Krishna, Rama, and Buddha, and that He will come again. It can almost be demonstrated that after each 500 years the world sinks, and a tremendous spiritual wave comes, and on the top of the wave is a Christ.

There is a great change now coming all over the world, and this is a cycle. Men are finding that they are losing hold of life; which way will they turn, down or up? Up, certainly. How can it be down? Plunge into the breach; fill up the breach with your body, your life. How should you allow the world to go down when you are living?