Malik bin Umayr (may Allah be pleased with him), who had lived through the Jahiliyyah, said: A man came to the Prophet (peace and blessings be upon him) and said: I met the enemy, and my father was among them. I heard him say something vile about you, and I could not restrain myself; I struck him with a spear, and as a result he was killed. The Prophet (peace and blessings be upon him) remained silent about it. Then another man came and said: I met my father and left him, and I wanted someone other than me to deal with him. The Prophet (peace and blessings be upon him) remained silent again.
This is a good mursal report.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17836