Musnad Ahmad 333:20

Hammad narrated to us, from Yazid, from Salamah, who said: Amir was a man who composed poetry, and he dismounted to chant (huda). He said: "O Allah, were it not for You, we would not have been guided, nor would we have given charity, nor would we have prayed. So forgive, may I be sacrificed for You, what we have committed, and make firm our feet if we encounter (the enemy). And cast tranquility upon us; for if we are called, we come." And with the shouting, they relied upon us. The Messenger of Allah (ﷺ) said: "Who is this chanter?" They said: "Ibn al-Akwa." He said: "May Allah have mercy on him." A man said: "It has become incumbent (that he be granted Paradise), O Messenger of Allah; if only you had let us enjoy him longer." He said: So he was struck. He went to strike a Jewish man from [the tribe of] Khaybar, but the edge of the sword struck the center of his own knee. The people said: "His deeds have been rendered void; he has killed himself." He said: So I came to the Messenger of Allah (ﷺ) after he had arrived in Medina, and he was in the mosque. I said: "O Messenger of Allah, they claim that Amir’s deeds have been rendered void." He said: "Who says that?" I said: "Some men of the Ansar, among them so-and-so and so-and-so." He said: "Whoever said that has lied. Indeed, he has two rewards"—and he gestured with his two fingers—"and he is a striver and a struggler. And rarely has an Arab walked who has surpassed him in that."