Sura al-Imran [Medina]

وَلاَ تَكُونُواْ كَالَّذِينَ تَفَرَّقُواْ وَاخْتَلَفُواْ مِن بَعْدِ مَا جَاءهُمُ الْبَيِّنَاتُ...

3:105. Be not like those who are divided amongst themselves and fall into disputations after receiving clear signs;

...وَأُوْلَـئِكَ لَهُمْ عَذَابٌ عَظِيمٌ ﴿١٠٥﴾

for them is a dreadful penalty.