Shams of Tabriz’s 
40 Rules of Love

Rule 7

Whatever happens in your life, no matter how troubling things might seem, do not enter the neighbourhood of despair. Even when all doors remain closed, God will open up a new path only for you. Be thankful! It is easy to be thankful when all is well. A Sufi is thankful not only for what he has been given but also for all that he has been denied.