The purpose of meditation is to cultivate positive states of mind that are conducive to inner peace and well-being, and to help us overcome negative habits of mind.
If we examine our life we can see that most of our time and energy is devoted to arranging our external circumstances and relationships. Although this can make us happy for a short time, it is not enough to help us find the deep and lasting contentment that we long for.
Happiness is a state of mind, therefore the real source of happiness lies in the mind, not in external situations. If our mind is peaceful we will experience happiness, regardless of our external circumstances, but if it is not peaceful we will never find happiness, no matter how successful we are in improving our external conditions. The method to make our mind peaceful is through meditation.