Takhrij Hadith 680: ""Whenever two-thirds of the night…"

"Whenever two-thirds of the night had passed, the Messenger of Allah (peace and blessings be upon him) would stand and say: 'O people! Remember Allah, remember Allah! The first blast of the Trumpet has come, followed by the second blast; death has come with all that it entails, death has come with all that it entails!' Ubayy said: 'I said: "O Messenger of Allah, I frequently send prayers upon you. How much of my supplication should I devote to sending blessings upon you?" He replied: "As much as you wish". I said: "A quarter?" He said: "As much as you wish, but if you increase it, it will be better for you". I said: "Then a half?" He said: "As much as you wish, but if you increase it, it will be better for you". I said: "Then two-thirds?" He said: "As much as you wish, but if you increase it, it will be better for you". I said: "Then I will devote all of my supplication to sending blessings upon you". He replied: "Then your worries will be taken care of, and your sins will be forgiven."'