This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahi Fazail-e-Amaal.
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said:
لا يجتمع كافر وقاتله فى النار أبدا .
"The disbeliever and the one who kills him will not be together in Hell."
Reference: Sahih Muslim, Kitab al-Imarah, Bab Man Qatala Kafiran Thumma Saddada, No: 1891.