Surah 68. Al-Qalam, Ayah 45

The term "subtle scheme" (kayd) evidently circumscribes here God's unfathomable plan of creation of which man can glimpse only isolated fragments and never the totality: a plan in which every thing and happening has a definite function, and nothing is accidental. (See in this connection note [11] on 10:5 - "None of this has God created without [an inner] truths.) Indirectly, the above passage alludes to the question as to the reason why God allows so many evil persons to enjoy their lives to the full, while so many of the righteous are allowed to suffer: the answer being that during his life in this world man cannot really understand where apparent happiness and unhappiness ultimately lead to, and what role they play in God's "subtle scheme" of creation.