Qays bin Abi Hazim (may Allah have mercy on him) says that Sayyiduna Ammar (may Allah be pleased with him) said: "Bury me in my own clothes, for I will be a disputant (pleading my case)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6823
Al-Ayzar bin Hurayth (may Allah have mercy on him) narrates that Zayd bin Suhan (may Allah be pleased with him) said: Do not wash the blood off me, and do not remove any garment from me except the leather socks, and bury me level in the earth, for indeed I am a man who will plead my case. In the narration of Abu Nu'aym there is the addition: I will plead my case on the Day of Resurrection.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6824
Imam al-Sha'bi (may Allah have mercy on him) narrates that Sayyiduna Ali (may Allah be pleased with him) offered the funeral prayer over Sayyiduna Ammar bin Yasir and Hashim bin Utbah (may Allah be pleased with them both); he placed Ammar next to himself and Hashim in front of him, and when they were lowered into the grave, Ammar was lowered first and then Hashim, who had been next to him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6825