When we sing the melodies that were written by Kabbalists or read the Psalms or other Kabbalists’ writings, we need to understand that they are all written in the state of being adhered to the Creator. Thus, there is no issue here of sadness, pessimism, or feeling of difficulty in the work.
Everything that seems as the expression of weakness or sadness are completely opposite feelings and specifically come from hope, from longings for love, from within the Light that already illuminates from afar, like the dawn rising.
These melodies can sound minor, in sadness, with a feeling of heaviness and weakness, but it is not at all this way. They come from a passionate desire, adhesion, joy, and devotion. Try to sing and feel them specifically in this way.
The same is true of the Psalms. All the most seemingly tragic poetry of David crying about how he has to run away from everyone who persecutes and hates him, and is abandoned by the Creator, all were written from a very high level of adhesion. We need to try to feel that in these melodies.
From the Preparation for the Daily Kabbalah Lesson 9/11/13