Nothing is certain. Only death is certain. Life has no certainty.
The king of today could be the beggar of tomorrow. The man from humble beginnings could rule the world. Life has no certainty.
Your lover today could break your heart tomorrow. Your enemy of yesterday could be your buddy tomorrow. Life has no certainty.
Your mind could be troubled by the uncertainties. You need to accept change with grace. Then, your mind will have certainty. Calm, patient, and untroubled by the turbulence outside. Your mind needs certainty even though life has no certainty.