Ali bin Abu Talib reported,
The Messenger of Allah ﷺ said, "Were it not that I would impose hardship on my community, I would have commanded them to use the toothstick before every prayer, and I would have delayed the night prayer until a third of the night had passed. For when the first third of the night has gone, Allah 
descends to the lowest heaven and remains there until dawn breaks, saying, 'Is there anyone asking, that he may be given? Is there anyone calling, that he may be answered? Is there anyone seeking intercession, that intercession may be granted? Is there anyone repenting and seeking forgiveness, that he may be forgiven?'"
Azami 305
Hasanعن علي بن أبي طالب
أن رسول الله ﷺ قال: لولا أن أشق على أمتي أمرتهم بالسواك عند بالسواك عند كل صلاة، ولأخرت المشاء الآخرة إلى ثلث الليل، فإنه إذا مضى ثلث الليل الأول هبط الله تبارك وتعالى إلى السماء الدنيا، فلم يزل هنالك حتى يطلع الفجر يقول: ألا سائل فيعطي، ألا داع يجاب ألا مستشفع فيشفع، ألا تائب مستغفر فيغفر له.
to the lowest heaven to the lowest heavenBazzar (477, 478) narrated it, he said, Sulayman bin Sayf Harrani told us, Saeed bin Bazi told us, from Ibn Ishaq, who said, Abdul-Rahman bin Yasar told me. Another chain, Ibrahim bin Saeed Jawhari, Fadl bin Sahl, and Ahmad bin Mansur told us, they said, Yaqub bin Ibrahim bin Saad told us, from his father, from Ibn Ishaq, who said, Abdul-Rahman bin Yasar told me, from Ubaydullah bin Abu Rafi, from his father, from Ali bin Abu Talib, and he related the hadith. Bazzar said, "The wording is the wording of Saeed bin Bazi, and this hadith has been narrated from the Prophet ﷺ through several routes, but we do not know of it being narrated from Ali, from the Prophet ﷺ, except through this route with this isnad." End of quote.Its isnad is hasan because of Saeed bin Bazi, who is Harrani. Abu Zura said of him, "Truthful," in Jarh wa Tadil (8/4). Muhammad bin Ishaq is a mudallis, but he explicitly stated "he told me" here. Abdul-Rahman bin Yasar is the Qurashi, their freedman, who narrated from Ubaydullah bin Abu Rafi, and from him narrated his nephew Muhammad bin Ishaq. Ibn Main deemed him reliable, and Ibn Hibban mentioned him among the trustworthy narrators in Thiqat. See Tajil Manfaa (654).I say, this is how Muhammad bin Ishaq explicitly stated it in the narration of Imam Ahmad (968), Darimi (1492), and Daraqutni in Nuzul (1), where he said, "My uncle Abdul-Rahman bin Yasar told me," except that Ahmad and Darimi did not mention the wording of the hadith, but instead referred to the wording of Abu Hurairah. The hadith of Abu Hurairah will come later in the Book of Purification, chapter on the tooth-stick, with a portion of it in the Book of Prayer, a portion in the chapter on prayer times, and the third portion has already preceded shortly before.Imam Ahmad (967, 10618) and Darimi (1491) combined it all into a single hadith, and both narrated it through the route of Muhammad bin Ishaq, who said, Saeed bin Abu Saeed Maqburi told me, from Ataa, the freedman of Umm Sabiyah, from Abu Hurairah. Ataa the Madinan, freedman of Umm Sabiyah, is unknown, and although Muhammad bin Ishaq used the form "from" (an ana) in some narrations, he did explicitly state "he told me" in others.