He lets his mind pervade one quarter of the world with thoughts of love, and so the second, and so the third, and so the fourth. And thus the whole wide world, above, below, around, and everywhere, does he continue to pervade with the heart of love, far-reaching, exalted, beyond measure. Verily this is the way to a state of union with Brahma. All humanity should walk the path of love. True peace and a world of joy cannot be realized without love.
Happiness is the same.
You can only feel true happiness when you are able to have a reciprocal relationship of love with another. Freedom is the same. You don't feel tired in the place of true love. No matter how exhausted you are, if you are intoxicated with love and you burst into tears out of love then your tiredness will suddenly disappear. When you feel true love you don't feel hungry or tired.