Translation of the letter:
I am a will-wishing brother to you. I call you to distinguish between the truth and falsehood so that you do not perish, and I invite you to know the truthful from liars so that you do not remain in loss; because you have always been in loss since the first day; as your Lord has said: ﴿إِنَّ الْإِنْسَانَ لَفِي خُسْرٍ﴾; “Indeed, the human being is surely in loss,” and your deliverance from loss is contingent on two things, as the flying of birds in the heaven is contingent on two wings, and those two things are indeed faith and righteous deed; as He has said: ﴿إِلَّا الَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ﴾; “Except for those who believe and do righteous deeds.”
As for faith, it is belief in the truth and disbelief in falsehood, and this is not possible to achieve except by knowing the truth and falsehood, and as for righteous deed, it is acting on whatever the truth requires and avoiding whatever falsehood requires, and this too is not possible to achieve except by knowing the truth and falsehood. Therefore, knowing the truth and falsehood is inevitably the foundation and starting point of faith and righteous deed. The example of cognition in relation to these two is the example of the foundations in relation to a building, the head in relation to the body, or prayer in relation to other deeds. Will a building remain firm in its place if it has no foundations?! Or will a person benefit from the other organs of his body if he has no head?! Or Will Hajj and fasting be accepted from one who does not perform prayer?! In the same way, if one does not have cognition, he is not a believer, nor does his righteous deed benefit him.
I am telling you the truth: If one dies between Safa and Marwa or while hanging from the curtains of Kaaba, with the righteous deeds of all jinn and humankind, while not knowing the truth and its people from falsehood and its people, he has indeed died a death of the time of ignorance and gone to Hell. From here, it becomes obligatory for you to know the truth and its people from falsehood and its people and give preference to this knowing over every righteous deed, and you shall know that without this knowing, there is no faith for you, and neither prayer nor fasting nor Hajj nor Zakat will benefit you, and you will be among the losers.