Ubayy bin Kaab reported,
Whenever two-thirds of the night had passed, the Messenger of Allah ﷺ would rise and call out, "People, remember Allah, remember Allah! The first blast has come, followed by the second. Death has arrived with all it brings. Death has arrived with all it brings."Ubayy said, "I asked, 'Messenger of Allah, I send blessings upon you frequently. How much of my prayer should I devote to sending blessings upon you?'"He replied, "Whatever you wish."I said, "A quarter?"He said, "Whatever you wish, but if you increase it, that is better for you."I said, "A half?"He said, "Whatever you wish, but if you increase it, that is better for you."I said, "Two-thirds?"He said, "Whatever you wish, but if you increase it, that is better for you."I said, "Then I will devote all of my prayer to sending blessings upon you."He said, "Then your concerns will be taken care of and your sins forgiven."
Azami 10874
Hasanعن أبي بن كعب قال
كان رسول الله ﷺ إذا ذهب ثلثا الليل قام فقال: يا أيها الناس، اذكروا الله، اذكروا الله، جاءت الراجفة، تتبعها الرادفة، جاء الموت بما فيه، جاء الموت بما فيه. قال أبي: قلت: يا رسول الله إني أكثر الصلاة عليك، فكم أجعل لك من صلاتي؟ فقال: ما شئت. قال: قلت: الربع؟ قال: ما شئت، فإن زدت فهو خير لك، قلت: النصف؟ قال: ما شئت، فإن زدت فهو خير لك، قال: قلت: فالثلثين؟ قال: ما شئت، فإن زدت فهو خير لك، قلت: أجعل لك صلاتي كلها، قال: إذا تكفي همك، ويغفر لك ذنبك.
Tirmidhi (2457), Ahmad (21241–21242), and Hakim (2/421) all narrated it, all through the route of Sufyan, that is Thawri, from Abdullah bin Muhammad bin Aqeel, from Tufayl bin Abu bin Kaab, from his father, and he mentioned it. The wording given here is Tirmidhi's. Its chain of transmission is hasan because of Abdullah bin Muhammad bin Aqeel, for there is disagreement about him, though his hadith is hasan as long as no error in it becomes apparent. Tirmidhi also graded it hasan. Hakim said, "Its chain of transmission is sahih."The companions used to send blessings on the Prophet ﷺ on other occasions as well, all of these being excellent practices in addition to that one.1. In sermons. Abdullah bin Ahmad (837) narrated from Mansur bin Abu Muzahim, who said, Khalid Zayyat narrated to us, Awn bin Abu Juhayfa narrated to me, he said, "My father was among Ali's guard, and he was positioned beneath the pulpit." My father told me that he, meaning Ali, climbed the pulpit, praised Allah the Almighty and extolled Him, sent blessings on the Prophet ﷺ, and said, "The best of this nation after its Prophet is Abu Bakr, and the second is Umar." He said, "Allah the Almighty places good wherever He wills." Its chain of transmission is hasan because of Khalid Zayyat, for there is no harm in him.Sending blessings on the Prophet ﷺ during the sermon has also been reported from Ibn Masud, Amr bin As, Abu Musa Ashari, and others. Ibn Qayyim said in Jala Afham (p. 526), "... Sending blessings on the Prophet ﷺ in sermons was a well known and recognized matter among the companions 
altogether."2. When visiting his ﷺ grave. Malik narrated from Abdullah bin Dinar, from Ibn Umar, that he used to stand at the grave of the Prophet ﷺ, send blessings on the Prophet ﷺ, and pray for Abu Bakr and Umar. More than one narrator transmitted it this way from Malik, as Ibn Abdul-Barr stated in Istidhkar (6/262–263). Its chain of transmission is sahih.Yahya Laythi narrated it in Muwatta (399) from Malik, from Abdullah bin Dinar, who said, "I saw Abdullah bin Umar stand at the grave of the Prophet ﷺ, sending blessings on the Prophet ﷺ and on Abu Bakr and Umar." The scholars criticized Yahya for narrating it with this wording, as Ibn Abdul-Barr mentioned in Istidhkar.This account has also been narrated from Ibn Umar through other routes, including what Bayhaqi narrated in Shuab (3854) through the route of Muhammad bin Abdullah bin Numayr, who said, Muhammad bin Bishr narrated to us, Ubaydullah narrated to us, from Nafi, from Ibn Umar, that whenever he returned from a journey he would begin at the grave of the Prophet ﷺ, sending blessings and peace upon him and praying for him, without touching the grave, then he would greet Abu Bakr with peace, then say, "Peace be upon you, father."3. And on Safa and Marwa. Ibn Abu Shayba narrated in Musannaf (30253–30254) through several routes from Shaybi, from Wahb bin Ajda, who said, "I heard Umar say, 'When you stand on Safa, say the takbir seven times, and between every two takbirs, praise Allah and extol Him, send Allah's blessings on the Prophet ﷺ, and pray for yourself, and do the same on Marwa.'" Its chain of transmission is sahih.Ismail bin Ishaq Qadi narrated in Salat ala Nabi, as found in Jala Afham (p. 537), from Hudba bin Khalid, who said, Hammam bin Yahya narrated to us, Nafi narrated to us, that Ibn Umar used to say the takbir three times on Safa, saying, "There is no god but Allah alone, with no partner, His is the dominion and His is the praise, and He has power over all things." Then he would send blessings on the Prophet ﷺ, then he would pray and prolong his standing and supplication, then he would do the same on Marwa. Its chain of transmission is sahih.4. When going out to the market or to an invitation or similar occasions. Ibn Abu Shayba narrated in Musannaf (30429) from Waki, from Masaar, from Amir bin Shaqiq, from Abu Waail, who said, "Abdullah never attended a gathering or a banquet without standing to praise Allah and send blessings on the Prophet ﷺ, and if he happened to come across some overlooked spot in the market, he would sit there and praise Allah and send blessings on the Prophet ﷺ." Its chain of transmission is sahih.