Sayyiduna Abu Umamah al-Bahili (may Allah be pleased with him) reports this saying of the Prophet (peace and blessings be upon him): "Hold fast to standing (in prayer) at night (that is, offering voluntary prayers), for it was the habit of the righteous before you; it is a means of nearness to your Lord, it wipes out sins, and it restrains from wrongdoing."
Al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat; its chain contains Abdullah bin Salih, the scribe of al-Layth. Abd al-Malik bin Shu'ayb bin al-Layth said: He is thiqah (trustworthy) and reliable, while a group of the Imams declared this narrator da'if (weak).