مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3650
Musnad of Abdullah bin Mas'ood
It was narrated from Ibn Mas'ood (رضي الله عنه) that The Messenger of Allah (ﷺ) said: "When the last third of the night comes, Allah, may He be glorified and exalted, descends to the lowest heaven, then He opens the gate of heaven, then He stretches forth His Hand and says: ‘Is there anyone who is asking, so that he may be given what he asked for?' And He remains like that until dawn breaks."
Musnad Ahmad 3673A saheeh hadeeth, and its men are reliable]