Ašhadu an lā ʾilāha ʾilla-llāha, wa ʾašhadu anna ḥammad(an) ʿAbduhu wa rasūluhu - I bear witness that there is no god but Allah, and I bear witness that Mohammad is the Messenger of Allah.
In this world
60% of the people (Christians, Muslims, and All Abrahamic religions) proclaim that there is one God.
The deity of Adam, Enoch,Noah,Hud, Salih, Abraham / Abram, Lot, Ishmael, Isaac, Jacob / Israel, Joseph, Job, Dhul-Kifl, Jethro, Moses, Aaron, Samuel, David, Solomon, Elijah, Elisha, Isiah, Ezra, Jeremiah, Ezekiel, Daniel, Jonah, Zachariah, John (the Baptist), Jesus and Muhammed (Ahmad) approximately 1lack 24 thousand messengers ) (Peace be on all of them ) is One and the same, In Arabic Called Allah.
Atheists (16%) Proclaim that La Ilaha - Their no God.
Logically In sum the above two sets 76% together agree to some part of the Shahada La ilaha illallah.
Who brought this message of Allah to us, for Muslims its Muhammad (PBUH)
Now why should Allah only be the Deity?
Quran Says in Chapter Al-Ikhlas:
Say: He is Allah, the One and Only!
Allah, the Eternal, Absolute;
He begetteth not nor is He begotten.
And there is none like unto Him.
If something is One and only which is Eternal and Absolute; neither begetteth nor begotten And there is none like unto it, it is Allah. Logically if you think there cannot be more than one thing exists with these characteristics, then you can consider it as your deity, all good names are for it.
God is an English word, with which you can form goddess, godfather, godmother and so on. And no messenger of Allah has used this word to address him, not even Jesus as his revelation the Bible was in Hebrew.
Hence it cannot behold good to address the one who is free from all these characteristics.
Why is Muhammad(PBUH)the messenger of Allah?
Because he(pbuh) is the one who brought the messages of Allah.
