The Forty Principles of Religion by Imam Abu Hamid Al-Ghazali

Indeed, "The Forty in the Principles of Religion" is a valuable work left to us by Hujjat al-Islam Imam Abu Hamid al-Ghazali, may Allah have mercy on him. In it, he laid down the essence and cream of his books, even gathering in it the cream of the sciences of the Quran, as he said:

There is no doubt that conciseness and summarization gather what is subtle in meaning and rare.

How, when he gathered in it the essence of the treasures of his books and enriched them with knowledge and wisdom, like "Ihya' 'Ulum al-Din" (The Revival of the Religious Sciences), "Al-Iqtisad fi al-I'tiqad" (The Middle Path in Belief), and "Bidayat al-Hidayah" (The Beginning of Guidance), and other works that are landmarks in their field?

And how could it not be so, when the author is the Imam, the knower of God Almighty, the jurist, the fundamentalist, the thinker, and the educator Abu Hamid al-Ghazali, who combined kalām (dialectical theology) and the heart?

So, in this blessed book, there was a harmony between the rational and the transmitted, and the apparent and the hidden aspects of rulings?

The book's content: forty principles of religion, its pillars, and its foundations, interrelated according to four sections:

The first section: On the principles of beliefs upon which religion is built, and which are the first step in it, from which one starts.

The second section: On outward actions and acts of worship, which he explained thoroughly, clarifying their features and secrets.

The third section: On purifying the heart from blameworthy qualities; emptying it of what displeases its Lord, and preparing it to be worthy and ready for divine lights and Lordly knowledge.

The fourth and final section: On adorning it with praiseworthy qualities after purifying it.

All of this is so that man may know the details of the paths to happiness in knowledge and action, and it becomes easy for him to acquire its keys through struggle and contemplation, as he, may Allah have mercy on him, said in the introduction to the book.