The wisdom of Jesus warned men not to let the sun come down on their wrath, for their prayers would be profitless, their God unhearing. For the same reason, do not approach meditation with hatred towards someone in your heart. If you cannot get over the sense of injury he has created, practise some relaxation exercises first, slow and deepen the breath-cycle, make it even and rhythmic. Stretch the body out flat on a couch and let it lie still for five minutes. Only after all these preliminaries have cooled your indignation may you begin to meditate.
-- Notebooks Category 4: Elementary Meditation > Chapter 2: Place and Condition > # 292