Rabbi Moshe Cordovera who lived in Tsfas (Safed 1522-1570) revolutionized Kabbalah by systemizing perhaps an otherwise seemingly arbitrary collection of Kabbalistic teachings in the Holy Zohar (much like what the Shulchan Aruch (Code Of Jewish Law) did for the Gemarah/Talmud.)
Toward the end of his life he wrote a beautiful book in which he shows us - perhaps the most important calling of our time - how to let go of anger and resentment, and induce love, thereby not only acting in love - but as heaven is a reflection of earth - like mist rises and creates the clouds that become the rain (in an ongoing pattern) to cause that our destiny from G-d should likewise create greater love and blessings.
Much of the concepts in this book are based on the concept of Sefiros.
Sefiros are the ten spheres / levels (3 intellectual and 7 emotional) in which the Divine Energy which kind of first begins (or manifests, in the level of Kesser) Crown, moves through these levels.
Everything in the universe is a result and in imitation of these levels.
Hence as we engage say in love instead of resentment, we cause that the force of Divine energy which comes to us is likewise.
This book is a step by step guide to overcoming resentment and actually loving unconditionally.
