The Qur'an tells the Story of the Differences among the Children of Israel, and Allah judges between Them
Allah tells us about His Book and the guidance, proof and criterion between right and wrong that it contains. He tells us about the Children of Israel, who were the bearers of the Tawrah and Injil.
أَكْثَرَ الَّذِى هُمْ فِيهِ يَخْتَلِفُونَ
(most of that in which they differ.) such as their different opinions about `Isa. The Jews lied about him while the Christians exaggerated in praise for him, so the Qur'an came with the moderate word of truth and justice: that he was one of the servants of Allah, and one of His noble Prophets and Messengers, may the best of peace and blessings be upon him, as the Qur'an says:
It was the demand of love and affection the Holy Prophet ﷺ had for all human beings that he should save them all from the fire of jahannam by making them accept the message of Allah. It used to hurt him a lot if someone did not accept it. He used to feel as if someone's children were proceeding toward the fire by not heeding to the advice of his parents. Therefore, Qur'an has adopted different expressions to console him at many places. One such advice was contained in the sentence وَلَا تَحْزَنْ عَلَيْهِمْ وَلَا تَكُن فِي ضَيْقٍ مِّمَّا يَمْكُرُونَ (And do not grieve for them, and do not be straitened because of what they plan - 27:70) which has appeared in the earlier verse. In the above verse he has been consoled in a slightly different manner, that his job was only to convey the message of truth, which he had done admirably. If someone had not accepted this, it was not his fault or deficiency. So, he need not worry and be despondent. Rather it is their own fault that they have lost their sense of direction. Qur'an has described the loss of their sense of direction by presenting three examples. First, that they were like dead bodies in the matter of acceptance of truth, and thus cannot take any one's advice to their advantage. Second, that they were like the deaf man who does not wish to hear anything, rather they turn their back and go away if someone tries to give them any advice. Third, that they were like the blind that cannot see even if someone tries to show them the path. After providing these three examples it is said:
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 75–80
The words ‘do not grieve’ are not meant to prevent the preacher from grieving. It is, in fact, meant to contradict the impression that Truth is helpless. It means that, in spite of unfavourable conditions, the Truth and supporters of the Truth will finally meet with success. When the adversaries of the preacher of Truth contradict him, they think that they are dealing with a human being. They do not understand that this is tantamount to setting themselves up against God Himself and not merely opposing an ordinary mortal. This state of affairs (i.e. the temporary success of the opponents) continues only till the expiry of the period of human trial. As soon this period is over, God will appear and all these opponents will vanish into thin air. There is no foolishness greater than mistaking the temporary respite during the trial period for unconditional and unlimited liberty to indulge in arrogance.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.