Having a relaxed mind is very useful in meditation. Relaxation is the foundation of deep concentration. When the mind is relaxed, it becomes more calm and stable. These qualities in turn strengthen relaxation, thus forming a virtuous cycle. Paradoxically, deep concentration is built on relaxation.A similar mechanism works in the practice of mindfulness. I found lightness to be highly conducive to mindfulness. Lightness gives rise to ease of mind. When the mind is at ease, it becomes more open, perceptive, and nonjudgmental. These qualities deepen mindfulness, which in turn strengthens lightness and ease, thus forming a virtuous cycle of deepening mindfulness.--Chade-Meng Tan in Search Inside Yourself; The Unexpected Path to Achieving Success, Happiness (and World Peace), (a 2012 book on meditation by an emotionally intelligent Google engineer), page 69.
Reference: ceremonial-magic.blogspot.com