Imam Ahmad ibn Hanbal said that the disbelievers asked prophet Muhammad peace be upon him to describe the God that he is preaching to. So Allah revealed these verses:
Say, “He is Allah, [who is] One,( 2 ) Allah, the Eternal Refuge.( 3 ) He neither begets nor is born,( 4 ) Nor is there to Him any equivalent.”
(1) قُلْ هُوَ اللَّهُ أَحَدٌ
Say, “He is Allah, [who is] One
He is the only God. He has no partners and no associates. Nothing is like him and nothing can be compared to Him.
(2) اللَّهُ الصَّمَدُ
Allah, the Eternal Refuge.
He is the one whom mankind adress in their needs. And He is their refuge in their calamities and tribulations.
(3) لَمْ يَلِدْ وَلَمْ يُولَدْ
He neither begets nor is born,
(4) وَلَمْ يَكُن لَّهُ كُفُوًا أَحَدٌ
Nor is there to Him any equivalent.
This is a simplified explanation from tafsir Al-Muyassar, tafsir Ibn-Kathir and tafsir Al-Qurtobi. Translation rights reserved.