Qays bin Bishr narrates from his father, who said: I heard Ibn al-Hanzaliyyah say: The Messenger of Allah (peace and blessings be upon him) sent out a detachment, and they met the enemy. A man from Banu Ghifar charged at one of the enemy and said: Take that, I am the Ghifari lad! A man said: He has nullified his reward. This was mentioned to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "There is no harm in his being rewarded and also praised."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5597