Musannaf Ibn Abi Shayba 21:250

Sharīk ibn ‘Abd Allāh narrated to us, from ‘Abd al-Malik ibn ‘Umayr, from Rajā’ ibn Ḥaywah, from Abū al-Dardā’, who said: Beware of the supplication of the oppressed, for it ascends to the heaven like sparks of fire until the gates of heaven are opened for it.