I am a layman, an average person with average or below average knowledge/intellect. But certain things are very clear to us lay/average people. One of them is this Slogan of 'Only Allah". I do not know which "The God" they are referring to when they say/demand 'Only God" in Command in the past, and "worship" today.
https://www.al-islam.org/nahjul-balagha-part-1-sermons/sermon-184-keep-silent-may-Allah-disgrace-you
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Today- its related to this phantom concept of their "version/definition" of the concept "Worship". This Slogan which on the surface looks True was/is Utilized by the ones looking to gain power/worldly gains. Causing many issues among the Muslims and is used as a rally point to plunder the wealth/property/land/places of worships/women & children and lives.
What is the reality of this call “ Only Allah”
1)Who is this God that call on?
2)How did this God communicate with them, Was it a direct communication?
3)How did this Group come to know of this God?
4)How do they understand what this God wants from them?
5)How do they prove what they understand is this God’s command to others?
6)How many Gods are there, every group/Individual in every age has a different interpretations of this God's commands?
7) Did the some Arabs, especially at or after the conquest of Mecca- who worshiped many gods, said let verbally accept one god, for political reasons, but we will undermine this man.
8) Why did Qur'an keeps reminding the Believers to Obey the Messenger of Allah(awj)?
9) Why they did not acknowledge the Authority of the Messenger of Allah(awj)?
10) How was this notion, used by internal and external enemy in the past and today to undermine Islam?
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https://www.al-islam.org/nahjul-balagha-part-1-sermons/sermon-7-they-have-made-satan-master-their-affairs
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These three Topic Shirk/Quranist/Psychological Warfare are important in this discussion.
http://www.shiachat.com/forum/topic/235034818-a-dialogue-on-your-understanding-of-shirk/
http://www.shiachat.com/forum/topic/235037162-the-quranist-movement/
http://www.shiachat.com/forum/topic/235035658-psychological-warfare-on-the-internet/