The outside of the grave is just earth, but inside it is regret and torment. The outside may be earth and carved stones, whilst inside it is disaster and calamity, boiling with grief and sorrow like a kettle, and no wonder, when they no longer get what they want of their desires and wishes. There are lessons in this world which need no further exhortation. It calls out: O dwellers of the earth, you have focused on building a realm that will soon pass away, and you have neglected the realm to which you are moving quickly. You have built houses in which others will live and enjoy them, and you have neglected houses for which there are no other inhabitants but you. This is the place where you will abide and bid farewell to work and toil. This is what matters, one of the gardens of Paradise or one of the chambers of Hell… End quote from al-Rooh (95).