قَالَ فَإِنَّهَا مُحَرَّمَةٌ عَلَيْهِمْ أَرْبَعِينَ سَنَةً يَتِيهُونَ فِي الْأَرْضِ فَلَا تَأْسَ عَلَى الْقَوْمِ الْفَاسِقِينَ ﴿۲۶﴾ وَاتْلُ عَلَيْهِمْ نَبَأَ ابْنَيْ آدَمَ بِالْحَقِّ إِذْ قَرَّبَا قُرْبَانًا فَتُقُبِّلَ مِنْ أَحَدِهِمَا وَلَمْ يُتَقَبَّلْ مِنَ الْآخَرِ قَالَ لَأَقْتُلَنَّكَ قَالَ إِنَّمَا يَتَقَبَّلُ اللَّهُ مِنَ الْمُتَّقِينَ ﴿۲۷﴾

﴾26﴿ Qaala fa innahaa muhar ramatun 'alaihim arba'eena sanah; yateehoona fil ard; falaa taasa 'alal qawmil faasiqeen
﴾27﴿ Watlu 'alaihim naba abnai Aadama bilhaqq; iz qarrabaa qurbaanan fatuqubbila min ahadihimaa wa lam yutaqabbal minal aakhari qaala la aqtulannnaka qaala innamaa yataqabbalul laahu minal muttaqeen

﴾26﴿ Allah Almighty said, then this land is forbidden for them, they will wander in the land for forty years - so do not be sad for the disobedient people
﴾27﴿ And recite to them the story of the two sons of Adam truly, indeed, when they offered sacrifices, they were sacrificed separately, so it was accepted from one (which was Abel) and not accepted from the other (which was Cain)

[26] This is the acceptance of the supplication of Moses (peace be upon him) and a mention of the worldly punishment upon that people. (Muḥarramah)—Most commentators have said that the term "taḥrīm" here implies prevention in its literal sense. Allah prevented them from entering; they were unable to come out of that place. Allah created unknown causes by which they could not exit. (Arbaʿīna Sanah)—Regarding the phrase "forty years," there are two opinions. The first is that it relates to "Muḥarramah," meaning the prohibition was temporary. After forty years, during the time of Yūshaʿ (peace be upon him), they were granted victory. (Yatīhūn)—Derived from "tīh," meaning confusion and aimless wandering. This punishment came upon them because they abandoned the obligation of jihad.
[27] The connection between this story and the previous one is from several angles. First, in the earlier account, abandoning battle against the disbelievers led to confusion and misguidance. In this story, unjustly killing a believing brother also resulted in irrationality and misguidance. (Ibnay Ādam)—The sound opinion is that these were the actual sons of Adam (peace be upon him) and Ḥawwā (peace be upon her). Some say they were from the Children of Israel, and their names were Hābīl and Qābīl (Abel and Cain). (Idh Qarrabā Qurbānan)—The apparent meaning of the Quran is that the reason for offering the sacrifice was the command of Allah, and there was no other cause. This also indicates that sacrificing is an ancient tradition. A qurbān is anything through which one seeks closeness to Allah. Hābīl’s sacrifice was the slaughtering of a sheep, while Qābīl’s was a few spoiled grains offered as charity. (Fatuqubbila Min Aḥadihimā)—At that time, the sign of acceptance was that fire would descend from the sky and consume the accepted offering. This is alluded to in verse 83 of Surah Āl ʿImrān. Hābīl’s offering was accepted, but Qābīl’s was not, due to a lack of taqwā (sincerity and piety). (Qāla La-Aqtulannak)—This statement arose from jealousy. The acceptance of Hābīl’s sacrifice was proof of his virtue, and this led Qābīl to become jealous. Some scholars mention that the first sin committed out of jealousy in the heavens was by Iblīs against Adam (peace be upon him), and the first sin committed out of jealousy on earth was by Qābīl against his brother. This disease of jealousy later spread among the Children of Israel and slowly transferred to this Ummah, as mentioned in hadith. (Qāla Innamā Yataqabbalu Allāhu Mina al-Muttaqīn)—This is a concise response. The detailed meaning is that acceptance is based on taqwā, and since you had no taqwā, the deficiency is from your own self—not from me, and I had no part in it.