Musnad Ahmad 986:8

Al-Hakam ibn Nafi’ narrated to us, Isma’il ibn ‘Ayyash narrated to us, from Buhayr ibn Sa’d, from Khalid ibn Ma’dan, from Kathir ibn Murrah, from Nu’aym ibn Hammar, that a man asked the Prophet, peace and blessings of Allah be upon him: "Which of the martyrs is the best?" He said: "Those who, when they meet in the ranks, do not turn their faces away until they are killed. Those are the ones who will recline in the high chambers of Paradise, and your Lord will laugh at them. And if your Lord laughs at a servant in the world, then there is no reckoning upon him."