Q 1:
What is the Tafsir (explanation/exegesis) of Allah’s saying (the meanings of which are translated as):
...but Allâh guides whom He wills.
A:
It means that it is Allah Who guides whomever He wills to goodness, rather than any of His servants, even Prophets, whose mission is only to give guidance through instruction and conveyance of the Message to people. Allah says addressing His Prophet (peace be upon him):
Verily you (O Muhammad صلى الله عليه وسلم) guide not whom you like, but Allâh guides whom He wills.
That is Allah’s Guidance, which is guidance directly bestowed by Allah Himself with full acceptance of the truth. Conveying guidance and directing humanity to the right path is referred to at the end of Surah Al-Shura in Allah’s saying:
And verily, you (O Muhammad صلى الله عليه و سلم) are indeed guiding (mankind) to the Straight Path (i.e. Allâh’s Religion of Islâmic Monotheism).
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.