Jealousy is the source of much anger, discontent and disharmony…

Jealousy is the source of much anger, discontent and disharmony. It feels like a thorn in our heart. When we are jealous our mind becomes narrow and obsessive, making it difficult for us to think of anything else or to see the situation from the other person's point of view. Jealousy is entirely futile because neither does it cause the other person's fortune or good qualities to decline, nor does it increase our own; all it does is to rob us of our own peace and happiness.

Venerable Geshe Kelsang Gyatso Rinpoche,
How to Understand the Mind