The recompense of  intentional murder  

 Allah Azza wa Galla says in Surat Alnesa'a aya 93: but whoever kills a believer intentionally, his recompense is hell, wherein he will abide eternally, and Allah has become angry with him, and has cursed him and has prepared for him a mighty punishment.

     This ayah carries a stern warning and promise for those who commit so grave a sin that it is mentioned along with polytheism in several verses of the Holy Quran, for instance Allah says in Surat Alfurqan aya 68:

    "And those who do not invoke with Allah another god, or kill the soul which Allah has forbidden (to be killed) except by right".

     and because of the story of the two sons of Adam (Habil and Qabil), Allah says in Surat Alma'eda aya 32:

     "Because of that, we prescribed for the children of Israel that whoever kills a soul not (to retaliate) for a soul killed, nor to punish for spreading disorder in the earth, is as if he killed the whole of mankind, and whoever saves the life of a soul is as if  he has saved the life of the whole mankind".

     in addition to these verses from the Holy Quran, there are many Hadiths from our prophet Muhammad peace be upon Him that prohibit murder.

      Our prophet said that the destruction of this earthly life is less significant before Allah than killing a Muslim (man or woman), and he said: blood offenses are the first disputes to be judged between the people on the day of resurrection.

     And in a  hadith that Abu Dawud recorded, Ubadah bin Alsamit states that the Messenger of Allah said: the believer will remain unburdened in righteousness as long as he does not shed prohibited blood,  when he sheds forbidden blood, he will become burdened.