It is obligatory upon every accountable person to believe correctly in Allāh and in the messenger صلى الله عليه وسلم. It is the best and most important of obligations. Believing in Allāh correctly is to have the complete certain conviction that God exists according to what befits Him. He exists without a doubt in His existence, without a how, volume, place, or direction. As for the belief in His messenger محمد peace be upon him, then one must have the conviction that Prophet محمد the son of ^Abdullāh is the messenger of God to the humans and the jinn and that he was truthful in everything that he conveyed from God.
The greatest of God’s rights upon His slaves is to worship Him knowing what befits Him, and that is the ultimate submission. To know God is to know what He is attributed with like having no beginning, being the only Creator, knowing all, and non-resemblance to the creations. To know God is to know what is impossible for Him to be attributed with like having a partner, limit, size, form, shape, image, residing in a place or a direction. Imām Ahmad Ar-Rifā^iyy said “The ultimate knowledge that you will have about God is to believe with certainty that God exists without a how and without a place”. This means that the ultimate knowledge that a slave can know about God is to have the conviction without any doubt that God exists without a how and without a place. His saying without a how is an explicit negation of attributing a body, shape, movement, stillness, attachment, detachment, and sitting to God. The how means the attributes of the creations. Knowing about the messenger peace be upon him is to know what is obligatory to be among the attributes of the prophets and what is impossible to be among their attributes and what is permissible for them to be attributed with.
It is obligatory to believe in the prophethood of our master محمد peace be upon him along with the belief in God. Combining the belief in both testifications of faith is necessary for one to be saved from the everlasting torture in hellfire , because the one who believes that God exists and doesn’t believe in the prophethood of محمد then such a person is not a believer (mu’min) nor a muslim.
Fellow Muslims, one must differentiate between those who are Muslims and those who are not. It is an obligation for one to believe in Allāh and in His messenger to be a Muslim, a believer. No attention is paid to whoever goes against that and says that the muslims and non-muslims are equal and calls people to worship whatever they want other than God. Indeed, the afterlife is approaching and the questioning on judgment day is real and the most important thing one will be judged about is the belief. It is narrated that some blasphemers from Quraysh asked the prophet to worship their idols for one year and they would worship his God for one year, then surat Al-Kāfiroun was revealed. Among its meanings is O Muhammad say O you blasphemers (kafiroun) I do not worship now, nor will I ever worship what you worship and you will not worship what I worship now or ever because Allāh knew eternally that you were not going to believe, and then there is an emphasis to those blasphemers that they will for sure die as blasphemers and that they have their invalid belief which is worshipping the idols while the Prophet has his belief which is the only correct religion, al-Islam. This is a very strong way to disassociate from idol worship. The same emphasis and threat was confirmed in the verse
فمن شاء فليؤمن ومن شاء فليكفر
which means whoever chooses the correct belief then he will not be in the bad situation of the one who chooses blasphemy, rather, the one who chooses blasphemy is punished and the one who chooses the correct belief is rewarded; the rest of the verse supports this meaning, where it says that Hellfire has been prepared for the blasphemers.
We ask God to make us live as muslims and to make us die as muslims and to keep us away from misguidance.