House on the rock, not in the sand. (Bible parable concerning personal principles). Principles don't change. Also, rigity is good for rocks, not for human beings. (lesson concerning adaptability). Actions may change. But they never go against principles. Work a lot. Pursue the accomplisment of your profound personal duty. Have a great capacity of work. Do your best. Do what you think is good to others. This the sense of life to me.