54:11 And so We caused the gates of heaven to open with water pouring down in torrents.
The noun dhikr primarily denotes “remembrance”, or – as defined by Raghib – the “presence [of something] in the mind”. Conceptually, and as used in the above context as well as in verses 22, 32, and 40, this term comprises the twin notions of understanding and remembering, i.e., bearing something in mind.
54:12 And caused the earth to burst forth with springs so that the waters met for a purpose pre-ordained.
As mentioned in 69:6-8, this wind – obviously an exceptionally violent sandstorm – raged without break for seven nights and eight days. For particulars of the tribe of ‘Ad, see the second half of note 48 on 7:65.
54:13 But him We bore on that [vessel] made of [mere] planks and nails.
For the general implication of this rhetorical question, see note 2 on 50:2. For the story of the tribe of Thamud, their prophet Salih, and the incident of the she-camel see 7:73-79, 11:61-68,26:141-158, and the corresponding notes.
54:14 And it floated under Our eyes, a recompense for him who had been rejected with ingratitude.
i.e., soon. In classical Arabic, the term ghadan (“tomorrow”) often applies to a relatively near future, signifying “tomorrow” (in its literal sense) as well as “in time” or “soon”. Hence – as pointed out by all authorities – it may have been used in the above context with reference to the Last Hour, which in the first verse of this very surah is spoken of as having “drawn near”.
54:15 And, indeed, We have caused such [floating vessels] to remain forever a sign [of Our grace unto man]: who, then, is willing to take it to heart?
For this and other Qur’anic references to the she-camel that was to be “let loose as a test” for the Thamud, see surah 1, note 57. God’s “letting her loose” is in this context evidently synonymous with “allowing her to become” a test.
54:16 And how severe is the suffering which I inflict when My warnings are disregarded!
i.e., between their own herds and the ownerless she-camel: see 26:155 and the corresponding note 61.
54:17 Hence, indeed, We made this Qur’an easy to bear in mind, who, then, is willing to take it to heart?
For the above rendering of ~aqara, see note 61 on 7:77.
54:18 To the truth gave the lie [the tribe of] ‘Ad, and how severe was the suffering which I inflicted when My warnings were disregarded!
See note 98 on 11:67.
54:19 Behold, We let loose upon them a raging stormwind on a day of bitter misfortune.
Sc., “of chastisement”: see 11:82 and the corresponding note 114. – The story of Lot and the people among whom he dwelt is mentioned in several places, most extensively in 11:69-83.
54:20 It swept the people away as though they were palm-trunks uprooted.
See 11:77-79 and the corresponding notes.