From the first of the six pillars of Eemaan is Eemaan (Belief) in Allaah.
• Belief in Allaah, the One free from defect, includes believing that He is the [only] true deity deserving of worship, as opposed to anything else that is worshipped. This is because He is the sole Creator of the slaves, the One who is fully aware of both their secrets and that which they openly manifest. He is the One who rewards those who obey Him and punishes those who disobey Him. It is for this worship that Allaah created the humans and the jinn and He commanded them with it. He the Exalted says,
وَمَا خَلَقْتُ الْجِنَّ وَالْإِنسَ إِلَّا لِيَعْبُدُونِ [٥٦] مَا أُرِيدُ مِنْهُم مِّن رِّزْقٍ وَمَا أُرِيدُ أَن يُطْعِمُونِ [٥٧] إِنَّ اللَّهَ هُوَ الرَّزَّاقُ ذُو الْقُوَّةِ الْمَتِينُ
“And I did not create the jinn and mankind except that they should Worship me [alone]. I seek no sustenance from them, nor do I ask that they should feed me. Verily Allaah is The Provider, Lord of Power, The Strong.”
• Belief in Allaah also includes the belief in all that he has made obligatory upon His slaves such as the five pillars of Islaam. The five pillars are:
Testifying that none has the right to be worshipped except Allaah and that Muhammad صلى الله عليه وسلم is the Messenger of Allaah
Establishing the prayer (Salaah)
Giving the charity (Zakaah)
Performing Hajj to the House of Allaah for those who are able; and the other obligations come in the pure Shari’ah.
• Belief in Allaah also includes the belief that he is the sole Creator of the universe, the One who Regulates and Governs the affairs to His creations in accordance with His Knowledge and Power.
• Belief in Allaah also includes the belief that He sent that Messengers and revealed the Books in order to correct and purify the slaves, and to call them to that which would correct them.
• Belief in Allaah also includes believing in His beautiful Names and Attributes. They are mentioned in His Great Book and have been affirmed by His trustworthy Messenger صلى الله عليه وسلم.
— Shaykh Ibn Baaz رحمه الله| The correct Islamic Aqidah & that which opposes it.[Paraphrased from Pg.16-22]