Quran

These righteous predecessors: Ibn Masoud, Alhasan, Ikrimah, Qatadah, and Muqatil all said in the meaning of this verse (as He should be feared): He is to be obeyed and not disobeyed, to be thanked and not denied, and to be remembered and not forgotten. Ibn Taimyah: 2/116.
Question: What is meant by fearing Allah, the Almighty, as He should be feared?

Meaning: Preserve your faith while you are well and safe, so that you die as Muslims. Allah, the Most Generous, has made it a habit of His generosity that whoever lives his life in a certain way, will surely die and be resurrected with the same. Ibn Kathir: 1/366.
Question: Why is it important to adhere to the commands of Allah in this life?

(All together), do not let anyone of you deviate from it, and when you find someone who has deviated from it -even slightly- bring him back to it. Do not debate nor neglect nor overlook him, lest all things fall apart, and you would be frustrated. You will remain like one who securely ties a bundle of arrows with a rope, not letting a single one become separated from the others. Al-Biqai: 2/131.
Question: What is the significance of the word (all) in the command to hold fast?

There is no evidence in this verse that it is forbidden to differ over minor issues since that is not a division. A division is what makes harmony and unity impossible. As for rulings on matters of jurisprudence, the disagreement regarding them is due to the deduction of precepts and the subtleties of the meanings of the Sharia. The Prophet's Companions continued to differ in the rulings on emerging issues, yet they were in complete harmony. Al-Qurtubi: 5/241.
Question: Is every difference in viewpoints considered a division and a rift?

This verse indicates that Allah loves for His servants to remember His blessings with their hearts and words, so that their gratitude and love for Him may increase, thus He would increase His bounty and blessings upon them. The greatest blessing of Allah that one may remember is the blessing of guidance to Islam. Al-Saadi: 142.
Question: How does a believer remember his Lord's blessings? What is the benefit of this remembrance?

People have different levels of responsibilities when it comes to changing evil and enjoining good: the scholars' duty is to alert the Rulers and Governors, and advise them of corrective actions. The duty of Rulers is changing evil with their power and authority. The duty of common people is protesting evil acts verbally and reporting them to the authority. This applies to acts of evil that can be permanent. If someone sees an obvious evil such as robbery, adultery, and the like, one should it change himself promptly in accordance with his capability. Ibn Atiyah: 1/486.
Question: People have different levels of responsibilities when it comes to enjoining good and forbidding evil. Explain.

Their faces will turn dark because of the disgrace, humiliation and shame in their hearts. The faces of the blessed will turn bright because of the joy, happiness, blessing and contentment in their hearts, the effects of which will appear on their faces. Al-Saadi: 341.
Question: Muslims' faces will turn bright while the disbelievers' faces will turn dark. Why?