Not all of the names come directly from the Quran. Around 81 names appear in the Quran. The remaining names have been taken from authentic hadiths, or derived by scholars from verbs and attributes found in the Quran and Sunnah.

This is also why different scholars have compiled slightly different lists. Some scholars only took names that appear directly as nouns in the Quran. Others also derived names from verbs and attributes. Because of these differences in approach and methodology, the lists vary from one scholar to another.

This also explains why two names with a similar meaning are sometimes listed separately. Even when two names relate to the same quality, they differ in grammatical form and in the depth of their meaning. For example, Al-Ghaffar (الغَفَّار) points to Allah forgiving repeatedly and continuously, while Al-Ghafoor (الغَفُور) points to the vastness of His forgiveness, His complete ability to cover even the greatest of sins. Each name reveals something unique about Allah, so both are kept as separate names.

As for the source of these lists, the most well-known reference for the enumerated names of Allah is the hadith of Abu Hurayrah R. narrated in Sunan at-Tirmidhi (no. 3507) and a narration in Sunan Ibn Majah. The core hadith is authentic. However, regarding the specific list of names attached to it, scholars have differed. The more cautious position is that the enumerated list was added by narrators and scholars, not that it forms part of the direct words of the Prophet (ﷺ). That said, every name in these lists has a basis in the Quran or Sunnah. None of them was invented or added from outside the Islamic sources, which is why scholars across generations have accepted and taught them.