Musnad Ahmad 30:3522

Aswad ibn Amir narrated to us, Abu Bakr narrated to us, from al-A'mash, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "Whoever sustains a wound in the way of Allah the Almighty and Majestic, he will come on the Day of Resurrection in its [original] state; its color will be the color of blood, and its scent will be the scent of musk." And it was narrated to us from Sharik also—meaning Aswad.