Quran

Allah says, (establish prayer), and did not say, "pray" so that the aim is to fulfill all of the prayer's conditions, and complete it properly, not just to perform it. Al-Alusi: 14/225.
Question: Allah says, (establish prayer), and did not say, "pray". Why?

Establishing prayer and giving zakah are the most important physical and financial acts of worship. Whoever does them in the manner prescribed, has fulfilled his duty toward Allah and His servants. Al-Saadi: 847.
Question: Among all acts of worship, establishing prayer and giving zakah are singled out for mention. Why?

(And obey Allah and His Messenger), what matters in all of that is sincerity and doing them properly. Hence Allah says: (And Allah is All-Aware of what you do). Allah knows their deeds, how they were done and the intention behind them, so He will requite them according to his knowledge of what was in their hearts. Al-Saadi: 847.
Question: After enjoining us to obey Him, Allah describes Himself as All-Aware of what we do. Why?

Al-Qushayri said: Whoever joins those who incurred someone's wrath, falls under the wrath of that person, and whoever joins those who incurred Allah’s wrath, will fall under Allah's wrath, which is sufficient humiliation, sorrow and deprivation. Al-Biqai: 19/387.
Question: What is the risk of joining those who incurred Allah's wrath?

Whoever lives his life adhering to something, will die in that state. Just as the hypocrites tried to deceive the believers in this world, swearing to them that they were believers, on the Day of Resurrection, when Allah raises them all, they will swear to Allah as they swore to the believers, thinking that their oath would benefit them, because their disbelief, hypocrisy, and false beliefs kept sinking deeper and deeper into their minds until they were thoroughly deceived by them and thought that they were following something worthwhile that would bring them rewards. Al-Saadi: 848.
Question: The hypocrites' ways in this life and the Hereafter are similar. How?

They oppose Allah and His Messenger because of their abundant followers, which makes those who are behind them believe that they possess the might that no one else has. Allah negates this apparent delusion by saying, (they), the lowlife and despicable (are among the most debased), they know that they are the most humiliated among people. Alhasan said: The sins have caused humiliation in their hearts despite their apparent vanities. Al-Biqai: 19/39.
Question: In light of this verse, what is the effect of sins on the hearts?

Al-Zajjaj said: The prevalence of the Messengers was two types: Whoever was sent with force, prevails in war, and whoever was not sent with force, prevails by argument. Al-Baghawi: 4/349.
Question: How did Allah's Messengers prevail over the deniers while some of the Messengers were killed by their people?