Verily, the subject matter of this treatise is extremely important and it is worthy of deep study and a good deal of time due to its magnitude, importance and urgent need. The happiness of the servant in his worldly life and Hereafter is dependent upon its fulfillment. There is no safety nor happiness for him in this worldly life or in the Hereafter unless he is from its people. Whoever studies the Book of Alläh and the Sunnah of His Noble Messenger knows its great and extensive importance as well as its loftiness: Truthfulness, it is a lofty, great rank from the various ranks of those who advance to Alläh Every action of the heart returns to it just as every corruption that occurs in the heart returns exclusively to its opposite, which is lying. So the source of every good in the outward and inward appearance of man is truthfulness and the source of every corruption in the outward and inward appearance of man is lying; thus good and corruption return back to these two sources.