Quran

(They invite unto the fire), means: By their words, deeds and attitude, so mixing with them poses a risk, not in worldly terms, but in terms of eternal doom. What we learn from this verse is that it is not allowed to mix with polytheists and the misguided, because if it is not permissible to marry them, even though doing so may serve many interests, then it is more appropriate to say that mixing with them in a regular manner is not allowed, especially in cases where a polytheist is in a higher position than the Muslim. Al-Saadi: 99.
Question: How do we infer from this verse the risk of mixing with the misguided and polytheists?

The intended meaning is that the believer should be cautious of what will harm him in the Hereafter, and should steer clear of any possibility of being in harm's way even though human nature and the devil push one into the direction of Hellfire. Al-Alusi: 2/120.
Question: When is a Muslim more likely to be in harm's way?

This verse consoles those who repeatedly fall into sin after repenting over and again; when going through that, they may fear being considered as liars and unworthy in the sight of Allah, and that may stop them from repenting. Al-Biqai: 1/422.
Question: The phrase "repentant" which means continuity is used in this verse. Why?

(And give glad tidings to the believers). There is no mention of what the glad tidings are about in order to indicate the general meaning, and that they will have glad tidings in this world and the Hereafter. Attaining all that is good and being protected from all that is evil as a consequence of their faith are included in these glad tidings. Al-Saadi: 100.
Question: Why is there no mention of what the glad tidings are about?

Meaning: Take fewer oaths by Allah to maintain His fear in your hearts. That is why Allah says, (Keep your oaths) [5:89], and He censured those who swear oaths excessively: (Do not obey any vile swearer of oaths) [68:10]. Al-Qurtubi: 4/13.
Question: What is the benefit of taking fewer oaths?

Allah forbade them from making the oath by Him a deterrent to doing what He commanded, lest they refrain from obeying Him with the oath they swore. Ibn Taimyah: 1/517.
Question: When is taking oath censured?

Then the verse concludes with these two noble names: (And Allah is All-Hearing) He hears all sounds. (All-Knowing) He knows people's aims and intentions. That includes His hearing of the words of those who swear oaths, and His knowledge of their intentions, whether they are good or evil. This is a warning that He will requite them for their deeds, and He has full knowledge of their actions and their intentions. Al-Saadi: 100-101.
Question: The verse concludes with emphasis on the importance of swearing an oath. Explain.