Is there a rhetorical wisdom behind the word "Al-Fath" (the conquest) being definite in the Almighty's saying: "When the help of Allah and the conquest come," and not saying "and His conquest" or "and Allah's conquest," as well as using "jaa'" (came) instead of "ata" (came/approached)?

"Al" in the word "Al-Fath" (The Victory) may be a substitute for the pronoun, making it equivalent to "Fathahu" (His victory), and this is part of the diversity of the Qur'anic style. Ibn 'Adil mentioned that "Al" in "Al-Fath" is a substitute for the annexation, meaning "Fathahu."

As for the difference between "Jaa'" (came) and "Ata" (came), Dr. Fadil Al-Samarra'i is of the view that the Holy Qur'an uses "Ata" for what is easier, while "Jaa'" is used for what involves difficulty and hardship, and this is a general characteristic in the Qur'an. So, "Jaa'" is used for great and difficult matters such as (Al-Sakhkhah - the deafening blast, Al-Tammah Al-Kubra - the greatest catastrophe, Nasr Allah - the help of Allah, and Al-Fath - the victory), while "Ata" is used for easier matters such as (the discourse of Al-Ghashiyah - the overwhelming event).