All growth depends upon activity. There is no development physically or intellectually without effort, and effort means work.
If the path be beautiful, let us not ask where it leads.
Don't go through life, grow through life.
It's one of nature's way that we often feel closer to distant generations than to the generation immediately preceding us.
There are seeds of self-destruction in all of us that will bear only unhappiness if allowed to grow.
There are no great limits to growth because there are no limits of human intelligence, imagination, and wonder.