The twenty-third juz’ of the Qur’an contains Surah Ya-Sin from ayah 28 till its end, Surah As-Saffat (Those Ranged in Ranks) and Surah Sad in their entirety and Surah Az-Zumar (The Groups) up to ayah 21.
Surah Ya-Sin, Surah As-Saffat, Surah Sad and Surah Az-Zumar are all Makkan Surahs.
From the Virtues of Surah As-Suffat
An-Nasai recorded that ‘Abdullah bin Umar, may Allah be pleased with him, said, “The Messenger of Allah, peace and blessings of Allah be upon him, used to command us to make our prayers short and he used to recite As-Saffat when he lead us in prayer.” (An-Nasai 2:95)
“And they say: ‘When will this promise (i.e. Resurrection) be fulfilled, if you are truthful?’ They await only but a single Saihah (shout) which will seize them while they are disputing! Then they will not be able to make bequest, nor return to their family. And the Trumpet will be blown (i.e. the second blowing) and behold from the graves they will come out quickly to their Lord. They will say ‘Woe to us! Who has raised us up from our sleep?’ (It will be said to them) ‘This is what the Most Gracious (Allah) had promised, and the Messengers spoke the Truth!’” (Surah Ya-Sin 36:48-52)
“And, when he (his son) was old enough to walk with him, he said: ‘O my son! I have seen in a dream that I am slaughtering you (offering you in sacrifice to Allah). So look what you think!’ He said: ‘O my father! Do that which you are commanded, InshaAllah (if Allah wills), you shall find me of As-sabirun (the patient).” (Surah As-Saffat 37:102)
“(This is) a Book (the Qur’an) which We have sent down to you, full of blessings, that they may ponder over its Verses, and that men of understanding may remember.” (Surah As Sad 38:29)
“[Iblis (Satan)] said: ‘My Lord! Give me respite till the Day the (dead) are resurrected.’ (Allah) said: ‘ Verily you are of those allowed respite, Till the Day of the time appointed.’ [Iblis (Satan)] said: ‘By Your Might, then I will surely mislead them all, Except Your chosen slaves amongst them.” (Surah Sad 38: 79-83)
“And when some hurt touches man, he cries to his Lord (Allah Alone), turning to Him in repentance. But when He bestows a favour upon him from Himself, he forgets that for which he cried for before, and he sets up rivals to Allah, in order to mislead others from his path. Say: ‘Take pleasure in your disbelief for a while, surely, you are (one) of the dwellers of the Fire!’ (Surah Az-Zumar 39:8)
“Allah has sent down the Best Statement, a Book (this Qur’an), its parts resembling each other in goodness and truth) (and) oft-repeated. The skins of those who fear their Lord shiver from it (when they recite it or hear it). Then their skin and their heart soften in the remembrance of Allah. That is the Guidance of Allah. He guides therewith whom He wills; and whomsoever Allah send astray, for him there is no guide.” (Surah Az-Zumar 39:23)
Surah Ya-Sin continues in this juz’ with its warning to the disbelievers of the consequences of not accepting the Message. They are told to look at the generations before that were destroyed for disbelief. Look at the signs in the earth, how the land appears dead but then is brought back to life, in the same way Allah will bring us back to life on the Day of Judgement. The disbeliever is arrogant and ungrateful for the bounties Allah has bestowed on them. Allah advises his Prophet, peace and blessings of Allah be upon him, not to let the vain speech of the disbelievers grieve him, and Allah knows what they conceal and what they reveal (36:76).
Surah As-Saffat continues with the theme of warning the disbelievers of a painful punishment. It testifies by the angels arranged in ranks, who drive the clouds and bring the Book, that verily Allah is One, and He is the Lord of the heavens and the earth and everything in it (37:1-5). Yet the disbelievers mock the signs and question the resurrection. On the Day of Judgement the angels will gather those who did wrong, and the companions they used to worship and lead them to the flaming Fire (37:22-23). The Prophets Nuh (Noah), Musa (Moses), Ilyas (Elias), Yunus (Jonah) peace be upon them all, are mentioned. The story of the Prophet Ibrahim (Abraham) peace be upon him, is continued in and we are told of when he was called to sacrifice his son, Ismail. They submitted themselves humbly to the Will of Allah and He blessed them for having passed the trial and called them sacrifice a ram instead (37:102-107). It is a reminder that we have to be prepared to sacrifice things we love for sake of Allah, and to follow His command even when it is difficult for us.
Surah Sad follows on closely from the themes of Surah As-Saffat making the point that the reason for disbelief is not any defect with the Message, but rather the arrogance of the people. The stories of Prophets Nuh (Noah), Lut (Lot) are mentioned. The Prophet Muhammad, peace be upon him, is enjoined to remember the incident when the Prophet Dawud (David) was a ruler and a group of people climbed over his wall and asked him to settle their dispute. He was taken aback and did not take time to properly consider the case. He ruled wrongly, then repented and sought forgiveness from His Lord and Allah forgave him. Dawud (David) was ordered to judge between men in truth and justice, (38:17-26) and all Muslims should do this also. We are told of how the Prophet Sulaiman (Solomon) was tested by Allah and repented and was forgiven, and how Prophet Ayyub (Job) was afflicted by trials, was patient, made du’a and was relieved.
Surah Az-Zumar is mainly addressed to the unbelievers, like the preceding Surahs. It opens with the testimony that the Qur’an is a true revelation calling people to worship Allah alone and perform good deeds. Allah is far above having any partners, He created everything in the heavens and the earth including our own selves, and is not in need of any helpers. They call on Him Alone when we are in need, but when times are good they forget their call and set up partners with Allah (39:8). Woe to those whose hearts are hardened against the remembrance of Allah.