(V.51:19) See the footnote of (V.4:37).

(V.51:28) i.e. when the angels noticed some fear over the face of Abraham, they told him that they are Allâh’s messengers. And they also gave the glad news to his wife Sarah that she will give birth to a son (Isaac).

(V.51:29) "How can I bear a child." At that time she (Sarah) was approximately 99 years old. (Tafsîr Al-Qurtubi ).

(V.51:30) a) The Statement of Allâh عز وجل: ‘Verily, Our Word (Command) unto a thing, when We intend it, is only that We say unto it: "Be!" - and it is.’ (V.16:40) Narrated Mu‘âwiyah رضي الله عنه: I heard the Prophet صلى الله عليه وسلم saying, "A group of my followers will keep on following Allâh’s Orders [i.e., following strictly Allâh’s Book (the Qur’ân) and the Prophet’s Sunnah (legal ways)] strictly and they will not be harmed by those who will belie (disbelieve) them or desert (stand against) them till Allâh’s Order (the Hour) will come while they will be in that state." (Sahih Al-Bukhari, Vol.9, Hadith No.552). b) Narrated Abu Hurairah رضي الله عنه: Allâh’s Messenger صلى الله عليه وسلم said, "Allâh said, ‘I have prepared for My pious slaves things which have never been seen by an eye, nor heard by an ear, or (even) imagined by a human being.’" (Sahih Al-Bukhari, Vol. 4, Hadith No. 467) c) Narrated Abû Sa‘îd Al-Khudrî رضي الله عنه: The Prophet صلى الله عليه وسلم said, "The people of Paradise will look at the dwellers of Al-Ghuraf (the lofty mansions i.e. a superior place in Paradise) in the same way as one looks at a brilliant star far away in the east or in the west on the horizon; all that is because of their superiority over one another (in rewards)." On that the people said, "O Allâh’s Messenger! Are these residences (lofty mansions) for the Prophets which nobody else can reach?" The Prophet صلى الله عليه وسلم replied, "No! By Him (Allah) in Whose Hand my soul is, these are for the men who believed in Allah and also believed in the Messengers." (Sahih Al-Bukhari, Vol. 4, Hadith No. 478) d) Narrated Abu Hurairah رضي الله عنه: Allâh’s Messenger صلى الله عليه وسلم said, "The first batch (of people) who will enter Paradise will be (glittering) like the moon on a full-moon night and those who will enter next will be glittering like the brightest star. Their hearts will be as if the heart of a single man for they will have neither difference nor any enmity amongst themselves, and everyone of them shall have two wives, each of whom will be so beautiful, pure and transparent that the marrow of the bones of their legs will be seen through the flesh. They will be glorifying Allâh in the morning and afternoon, and will never fall ill, and they will neither blow their noses nor spit. Their utensils will be of gold and silver, and their combs will be of gold and the fuel used in their censers will be of aloes-wood and their sweat will smell like musk." ... (Sahih Al-Bukhari, Vol. 4, Hadith No. 469).

(V.51:37) See the book of history "The Stories of the Prophets." by Ibn Kathir رحمه الله.

(V.51:44) Sâ‘iqah: A destructive awful cry, torment, hit, a thunderbolt, See (V.41:13).

(V.51:50) See the footnote of (V.3:85).

(V.51:60) A) See the footnote of (V.3:85). B) Narrated Anas رضي الله عنه: The Prophet صلى الله عليه وسلم said, "Allâh will say to the person of the (Hell) Fire who will receive the least punishment, ‘If you had everything on the earth, would you give it as a ransom to free yourself (i.e., save yourself from this Fire)?" He will say, ‘Yes.’ Then Allâh will say, ‘While you were in the backbone of Adam, I asked you much less than this, (i.e., not to worship others besides Me), but you insisted on worshipping others besides me.’" (Sahih Al-Bukhari, Vol. 4, Hadith No.551).