In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Shaikh Abdur-Razzaaq Al-Badr [may Allaah preserve him] stated as well as quoted a statement of Shaikhul Islaam Ibn Taymiyyah [rahimahullaah] regarding why the Salaf [pious predecessors] and those who followed their path wrote summarised books on Aqeedah- that they did so in order to briefly present the foundation of what distinguishes the Aqeedah of Ahlus Sunnah Wal Jamaa’ah from the Aqeedah of the unbelievers, and the Mubtadi’ah, such as the Jahmiyyah, the Mutazilah, the Qadariyyah, the khawaarij, the Mur’ji’ah, the Raafidah etc.
These summarised books of Aqeedah are a beginning for the student and paves the way for him to study the books of Aqeedah that are more detailed. Therefore, after knowing this, it not befitting [or appropriate] for a person to say that such and such scholar fell short in mentioning such and such in this or that summarised book. Those who utter this statement do not know the aim of the Salaf behind these summarised books of Aqeedah. That is because these summarised books of Aqeedah were written to make a brief distinction between the Aqeedah of Ahlus Sunnah and the Aqeedah of Ahlul bidah – accompanied by few examples in the subject matter. For example, when writing about the Attributes of Allaah in these summarised books of Aqeedah, they [i.e. Salaf and the scholars who followed their path] only mentioned some of the Attributes of Allaah, quoted their evidences and the principles regarding how to approach this subject matter, because the same principle applies to the rest of the Sifaat [i.e. the Attributes of Allaah]. Therefore, these summarised books of Aqeedah are very beneficial for the student of knowledge regarding the Aqeedah of Ahlus Sunnah Wal Jamaa’ah based on the Qur’aan and Sunnah as opposed to what ahlul bidah wal ahwaa are upon.
[Source: An Excerpt from Sharh Al-Aqeedah At-Tahaawiyyah. Lesson 1]