An unforgivable sin of the Children of Israel (i.e. Jewish) which made them to strike with abasement and indigence and to burden the wrath from God was the killing of the prophets. Some hadith sources released that they killed almost 300 prophets in one day.
It is reported that the Israelites, children of Israel, killed three hundred prophets in a single day.  The killing of the prophets (2:61, 87, 91; 3:21, 112, 181; 4:155; 5:70) is also mentioned several times in the Bible (Luke 13:34; Matthew 23:37; Romans 11:3; 1 Thessalonians2:14–15; 1 Kings 19:10).  The Qur’an introduces Zechariah and John as the Prophets who were killed by the children of Israel.  What makes the issue worse is that the children of Israel knew that they were prophets, and killing them would be a great sin. Based on the Islamic tradition, many prophets were killed by them in two different ways. They killed the prophets directly as mentioned above or they revealed the beliefs and secret sayings and teachings of the prophets to the tyrant rulers of that time or provoked them to kill the Prophets. So these rulers captured the prophets and killed them and actually, the Israelites had the prophets killed.  Moreover, there are some prophets who were threatened to be killed. Aaron, Moses’s brother, was one of them. The Qur’an narrates: “…And he [Moses] threw down the tablets and seized his brother by [the hair of] his head, pulling him toward him. [Aaron] said, "O son of my mother, indeed the people oppressed me and were about to kill me…” 
 Ad-Dur-o Al-Manthur, Soyuti, vol 1, p 73.
 See: Gabriel Reynolds’s article:
 Tafsir Al-Qur’an Al-karim, Seyed Abdullah Shubbar, p 49.
 Al-Mahasen, Barqi, vol 1, p 256.0
 Chapter 7, verse 150. وَأَلْقَى الْأَلْوَاحَ وَأَخَذَ بِرَأْسِ أَخِيهِ يجُرُّهُ إِلَيهِ قَالَ ابْنَ أُمَّ إِنَّ الْقَوْمَ اسْتَضْعَفُونِي وَكَادُوا يقْتُلُونَنِي