Allah says in the Qur’an:
The only saying of the faithful believers, when they are called to Allah (His Words, the Qur’an) and His Messenger (صلى الله عليه وسلم), to judge between them, is that they say: “We hear and we obey.” And such are the successful (who will live forever in Paradise). And whosoever obeys Allah and His Messenger (صلى الله عليه وسلم), fears Allah, and keeps his duty (to Him), such are the successful. [Surah An-Noor 24:51-52]
In these verses, Allah provides a very powerful insight into the attitude of a believer. When a Muslim is called to guidance, he simply obeys. This is different from the behaviour of the hypocrites or those who do not have emaan in their hearts – mentioned in verses 47-50 of the surah – who claim that they obey but they turn away when ‘Allah and His messenger judge between them.’ In other words, they demand something other than the truth because they do not wish to submit to Allah. 
No ifs and no buts: those that hear and obey, such are the successful. Let us now have a look at some important aqaid (beliefs) in Islam and, with painful honesty, ask ourselves if we hear and if we obey.
Light (noor) is a creation of Allah. Allah is not Noor. There is none like him.
All praises and thanks be to Allah, Who (Alone) created the heavens and the earth, and originated the darkness and the light; yet those who disbelieve hold others as equal with their Lord. (Al-Anaam 6:1)
And there is none comparable unto Him. [Al-Ikhlas 112:4]
Muhammad (SAW) was a man as were all other messengers. Muhammad (SAW) died after completing his mission. Only Allah is the Ever Living, the Al-Hayee, the Al-Qayyum.
Their Messengers said to them: “We are no more than human beings like you, but Allah bestows His Grace to whom He wills of His slaves. It is not ours to bring you an authority (proof) except by the Permission of Allah. And in Allah (Alone) let the believers put their trust. [Surah Ibrahim 14:11)
Say (O Muhammad صلى الله عليه وسلم): “I am only a man like you. It has been revealed to me that your Ilah (God) is One Ilah (God – i.e. Allah). So whoever hopes for the Meeting with his Lord, let him work righteousness and associate none as a partner in the worship of his Lord.” (Al-Kahf 18:110)
And We granted not to any human being immortality before you (O Muhammad صلى الله عليه وسلم): then if you die, would they live forever? (Al-Anbiya 21:34)
Verily you (O muhammad صلى الله عليه وسلم) will die, and verily they (too) will die. (Az-Zumar 39:30)
The dead cannot hear. Seeking intercession of the dead is shirk. Allah listens to all duas directly.
And they worship besides Allah things that harm them not, nor profit them, and they say: “These are our intercessors with Allah.” Say: “Do you inform Allah of that which He knows not in the heavens and on the earth?” Glorified and Exalted is He above all that which they associate as partners (with Him)! (Surah Yunus 10:18)
Nor are (alike) the living and the dead. Verily, Allah makes whom He wills to hear, but you cannot make hear those who are in graves. (Surah Fatir 35:22)
Obedience to Muhammad (SAW) and following his Sunnah is obligatory.
Say (O Muhammad صلى الله عليه وسلم): “Obey Allah and the messenger (Muhammad صلى الله عليه وسلم).” But if they turn away, then Allah does not like the disbelievers. (Aal-e-Imran 3:32)
The dead have no contact with the living. The living cannot transfer reward to the dead. All dead are in Barzakh receiving reward or torment, not in their earthly graves. Allah assigns a grave even to those who do not get a burial.
“So that I may do good in that which I have left behind!” No! It is but a word that he speaks; and behind them is Barzakh (a barrier) until the Day when they will be resurrected. (Al-Mumenoon 23:100)
(They are) dead, not living. And they know not when they will be raised. (An-Nahl 16:21)
Then He causes him to die and puts him in his grave. (Surah Abasa 80:21)
There is no life in the graves on this earth. There are only two lives: the first in this world and the second after resurrection on the Day of Judgement.
They will say: “Our Lord! You have made us to die twice (i.e. we were dead in the loins of our fathers and dead after our life in this world), and You have given us life twice (i.e. life when we were born and life when we are Resurrected)! Now we confess our sins, then is there any way to get out (of the Fire)?” (Tafsir Al-Qurtubi,) (Surah Ghafir 40:11)
Muhammad (SAW) was the last of the prophets.
Muhammad (صلى الله عليه وسلم) is not the father of any of your men, but he is the Messenger of Allah and the last (end) of the prophets. And Allah is Ever All-Aware of everything. (Al-Ahzab 33:40)
Those that argue against these beliefs, or beings arguments from famous scholars, need to stop and think again about what they believe in and why. This is also an appropriate moment to ask ourselves: do we hear and do we obey?
Assalam o alaikum
 This is the behaviour of those who claim to be Muslims but refuse to believe in the tenets of faith that collectively make up the Islamic belief system. For example, a majority of Muslims believes that Prophet Muhammad (SAW) is alive in his grave in Medina. Do they hear and obey?