It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that a man asked the Prophet (peace and blessings be upon him) about the night prayer, and he (peace and blessings be upon him) said: "It is two units (rak'ahs) at a time."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Ibn Awn, from Ibn Sirin, except Abu Asim."