Quran

This is addressed to both Moses (u) and Aaron (u), but the previous verse mentions that Moses (u) alone was supplicating which means that Aaron (u) was saying: "Amen." Ibn Juzay: 1/387.
Question: This verse proves that supplication is answered for the supplicant and the one who says: "Amen." Explain.

In addition to answering their supplication, Allah enjoined them to be steadfast on the straight path, which is done in gratitude to Allah for His favor upon them. Answering His servant’s supplication is a favor from Allah that merits offering gratitude to Him. The greatest form of gratitude to Allah is obeying Him. The essence of steadfastness is uprightness, which is the opposite of deviance, and it often used to mean adhering to the truth and the right course. Ibn Ashur: 11/273.
Question: What is the meaning of "steadfastness"? Allah enjoined them to be steadfast after accepting their supplication, why?

Belief is not beneficial then, and repentance is accepted only before facing death, but after witnessing one's own death, no repentance will be accepted. Al-Qurtubi: 11/45.
Question: When does accepting repentance and faith end?

This is the way of Allah; once the disbelievers reach the point at which they have no choice but to believe, belief will not benefit them because their belief is based on what they see with their own eyes, like the belief of one who is resurrected. The only belief or faith that is of benefit is the faith in the unseen. Al-Saadi: 372.
Question: Allah did not accept the belief of Pharaoh, why? What is the acceptable belief to Allah?

Hence, they may come across signs repeatedly, but they do not benefit from them because they have no interest in them. In contrast, the one who is alert and focused sees of the signs of Allah that which is the greatest evidence of the soundness of what the Messengers told us. Al-Saadi: 373.
Question: What prevents most people from benefiting from the abundant signs of Allah?

This is the problem that the followers of the true religion are faced with: if satan fails to make them obey him by abandoning religion completely, he strives to stir up troubles among them and create enmity and resentment among them, so that differences arise between them that lead them to brand one another as misguided, and developing grudges against one another, which will delight Iblees. Otherwise, as their Lord is one, their Messenger is one, their religion is one, and their public interests are the same, why would they differ in such a way that divides them, weakens them, dissolves the bonds between them, and thus is detrimental to their religious and worldly interests, and this detracts from their religious commitment. Al-Saadi: 373.
Question: What is the problem that weakened Muslims despite them having the right knowledge?

This is a guidance to anyone who has doubts about religious issues to seek knowledge from scholars, and do that swiftly as indicated by the verse. Al-Alusi: 11/252.
Question: What is the cure for doubts that come to mind?