In one of his many writings, sheikh al-Islam ibn al-Qayyim wrote the following important words :

كل آية في القرآن فهي متضمنة للتوحيد شاهدة به داعية إليه، فإن القرآن إمَّا خبر عن الله وأسمائه وصفاته وأفعاله فهو التوحيد العلمي الخبري، و إمَّا دعوة إلى عبادته وحده لا شريك له وخلع كل ما يعبد من دونه فهو التوحيد الإرادي الطلبي، و إمَّا أمر ونهي وإلزام بطاعته في نهيه وأمره فهي حقوق التوحيد ومكملاته، و إمَّا خبر عن كرامة الله لأهل توحيده وطاعته وما فعل بهم في الدنيا وما يكرمهم به في الآخرة فهو جزاء توحيده، و إمَّا خبر عن أهل الشرك وما فعل بهم في الدنيا من النكال وما يحل بهم في العقبى من العذاب فهو خبر عمن خرج عن حكم التوحيد، فالقرآن كله في التوحيد وحقوقه وجزائه وفي شأن الشرك و أهله وجزائهم

Every ayah in the Qur’an involves al-Tawheed – bearing witness to it and inviting to it.

The Qur’an is always one of the following:

○ Information about Allah, His names and attributes, His actions. This is the tawheed of knowledge and information.

○ Or it is is calling the people to the sole worship of Allah with no partners and doing away with everything else that is worshiped besides Him. This is the tawheed that is sought to be put into practice.

○ Or it is commands and prohibitions and mandating you to obey Him in His prohibitions and commands. This is actualizing al-tawheed and putting it fully into practice.

○ Or it is some information about Allah honoring the people who single Him out in worship and obey Him, and information about what He did for them in the life of this world and how He will honor them in the hereafter. This is the reward of this tawheed.

○ Or it is some information about the people of al-shirk and the punishment that He dealt to them in this worldly life and the punishment that He will unleash on them [in the hereafter]. This is information about those who left the fold of al-tawheed.

So the entire Qur’an is about al-tawheed, its actualization, and its reward, as well as dealing with the issue of al-shirk, those who practice it and their recompense.

📕[Madaarij al-Salikeen 3/450]