God is a Necessary (necessarily existent) Singular (simple & unique) Absolute (with absolutely free will) & Transcendent (distinct from all creation) being, from the scriptural definition of Allah in Chapter 112 of the Quran.
Argument:
1. A contingent being (a being such that if it exists it could have not-existed) exists. [ evident ]
2. This contingent being has a cause of its existence. [ follows from 1. ]
3. The cause of its existence is something other than itself. [ follows from 1. & 2. ]
4. This cause must either be a contingent or a non-contingent -necessary- being. [ law of excluded middle ]
5. Contingent beings solely are not sufficient for the existence of a contingent being. [ follows from 3. ]
6. This cause must include a necessary being. [ follows from 4. & 5. ]
7. Therefore, a Necessary being (a being such that if it exists cannot not-exist) exists. [ follows from 1. & 7. ]
8. Two necessary distinct beings exist. [ assumption ]
9. A difference between the distinct necessary beings exists. [ follows from 8. ]
10. This difference is either necessary or contingent. [ law of excluded middle ]
11. If the difference is necessary, then three necessary beings exist. [ absurd! ]
12. If the difference is contingent (has a cause or an explanation for its existence), then at least one of the two necessary beings is contingent (has a cause or explanation for its/their existence). [ absurd! ]
13. Therefore, a necessary being is one (i.e. unique). [ follows from 10. & 11. & 12.]
14. Similarly, a necessary being is simple (i.e does not have parts) [ substitute "necessary beings" with "parts" in 9. ]
15. Therefore, the necessary being is Singular (i.e. unique & simple). [ follows from 13. & 14. ]
16. The sum of all contingent beings is not singular. [ evident ]
17. Therefore, the sum of all contingent beings is Distinct from the necessary being. [follows from 15. & 16. ]
18. Therefore, the necessary being is Transcendent from the sum all contingent beings. [ follows from 17. ]
19. The sum of all contingent beings is contingent (not necessary, i.e. not identical to the necessary being). [ follows from 15. & 17. ]
20. The sum of all contingent beings is contingent on a necessary being. [ follows from 2. & 3. & 6. & 19. ]
21. The necessary being is the sole cause of the existence of the sum of all contingent beings. [ follows from 15. & 20. ]
22. The attribute to cause the sum of all contingent being exists (Will). [ evident from 19. ]
23. All contingent beings are equally non-existent prior to existence. [ evident ]
24. The Will is Absolutely Free. [ follows from 22. & 23. ]
25. Therefore, a Necessary & Singular & Transcendent & Absolute being exists. [ follows from 7. & 15. & 18. & 24. ]
C. Therefore, God exits. [ as defined in the Quran ]