This Ayah chastises the People of the Book for the transgression and prohibitions they committed by their denials in the past and more recent times, of Allah's Ayat and the Messengers. They did this due to their defiance and rejection of the Messengers, denial of the truth and refusal to follow it. They also killed many Prophets when they conveyed to them what Allah legislated for them, without cause or criminal behavior committed by these Prophets, for they only called them to the truth,

﴿وَيَقْتُلُونَ الَّذِينَ يَأْمُرُونَ بِالْقِسْطِ مِنَ النَّاسِ﴾

(And kill those men who order just dealings) thus, demonstrating the worst type of arrogance. Indeed, the Prophet said,

«الْكِبْرُ بَطَرُ الْحَقِّ وَغَمْطُ النَّاس»

(Kibr (arrogance) is refusing the truth and degrading people)

This is why when they rejected the truth and acted arrogantly towards the creation, Allah punished them with humiliation and disgrace in this life, and humiliating torment in the Hereafter. Allah said,

﴿فَبَشِّرْهُمْ بِعَذَابٍ أَلِيمٍ ﴾

(then announce to them a painful torment) meaning, painful and humiliating,

﴿أُولَـئِكَ الَّذِينَ حَبِطَتْ أَعْمَـلُهُمْ فِي الدُّنْيَا وَالاٌّخِرَةِ وَمَا لَهُم مِّن نَّـصِرِينَ ﴾

(They are those whose works will be lost in this world and in the Hereafter, and they will have no helpers. ).

﴿أَلَمْ تَرَ إِلَى الَّذِينَ أُوتُواْ نَصِيبًا مِّنَ الْكِتَـبِ يُدْعَوْنَ إِلَى كِتَـبِ اللَّهِ لِيَحْكُمَ بَيْنَهُمْ ثُمَّ يَتَوَلَّى فَرِيقٌ مِّنْهُمْ وَهُم مُّعْرِضُونَ - ذَلِكَ بِأَنَّهُمْ قَالُواْ لَن تَمَسَّنَا النَّارُ إِلاَ أَيَّامًا مَّعْدُودَتٍ وَغَرَّهُمْ فِى دِينِهِم مَّا كَانُواْ يَفْتَرُونَ - فَكَيْفَ إِذَا جَمَعْنَـهُمْ لِيَوْمٍ لاَّ رَيْبَ فِيهِ وَوُفِّيَتْ كُلُّ نَفْسٍ مَّا كَسَبَتْ وَهُمْ لاَ يُظْلَمُونَ ﴾

(23. Have you not seen those who have been given a portion of the Scripture They are being invited to the Book of Allah to settle their dispute, then a party of them turned away, and they are averse.) (24. This is because they say: "The Fire shall not touch us but for a number of days.'' And that which they used to invent in their religion has deceived them.) (25. How (will it be) when We gather them together on the Day about which there is no doubt (i.e. the Day of Resurrection). And each person will be paid in full what he has earned And they will not be dealt with unjustly.)