Regardless of who we are, the main purpose of our life, you could call it the heart of being human, is to be happy. All of us share the same wish and the same right to seek happiness and to avoid suffering. If we look closely we can see that there are two kinds of happiness: one is based more on material comforts and pleasures and the other is founded on a deeper mental contentment. The first kind can be very expensive and is often unsatisfying, while the second costs nothing at all and is deeply satisfying.
The great saints of the past used to say: it is the foolish that go looking for happiness outside of themselves; the wise and learned know that all happiness and the causes of happiness are present within us, in our own mind and heart.
If you have this deeper, inner peace and contentment, then even when you go through suffering, your mind can still be happy. Even when difficulties arise you’ll be able to turn them to your advantage. So, for your own inner peace and stability, taking care of your mind and heart is crucial. Once your own mind is more at peace, then both inner and outer harmony will automatically follow.