תּוֹרָה כב

When a person is joyful — the melancholy and afflictions are set aside. But there is a higher virtue — to strive to pursue the melancholy specifically — to transform it to joy. Like the way of one who enters into the joy — for then through the greatness of the joy and gladness one transforms all one's worries and sadness and melancholy into joy. And the understanding one will easily find in every trouble and affliction and worry some expansion — through which one can transform all the melancholy into joy. And this is the primary completeness of joy.