Is it obligatory to begin by praying for oneself before the believers, following the example of Quranic verses, such as the Almighty's saying: "Our Lord, forgive us and our brethren who preceded us in faith" (Quran 59:10)?

Concluding the Quranic recitation with "صدق الله العظيم" (Allah, the Most High, has spoken the truth) has no basis in the Sunnah. It is recommended for a Muslim to prioritize himself in supplication over others, based on what is narrated in prophetic hadiths, including the Tashahhud, and the saying of the Prophet, peace be upon him, when mentioning one of the prophets: "May Allah's mercy be upon us and upon my brother." This is also evident in the actions of the prophets such as Moses, Noah, and Abraham, peace be upon them, in their supplications. The actions of the believers also attest to this.