Naeem Mujmir narrates from the freed slave of Sayyiduna Umar bin Al-Khattab (may Allah be pleased with him) that Muhammad bin Abdullah bin Zaid Al-Ansari, who saw the dream of giving the Adhan during the time of the Messenger of Allah (peace and blessings be upon him) (the dream was seen by his father Abdullah as mentioned earlier and as in Muslim), informed that Sayyiduna Abu Mas’ud Al-Ansari Uqbah bin Amir (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) came to us and sat with us in the gathering of Sa’d bin Ubadah. Basheer bin Sa’d, who is Abu Nu’man bin Basheer, said to him: O Messenger of Allah! Allah Almighty has commanded us to send blessings upon you, so how should we send blessings upon you? He replied: “Say like this: «اللّٰهُمَّصَلِّعَلَىمُحَمَّدٍوَعَلىٰآلِمُحَمَّدٍكَمَاصَلَّيْتَعَلَىإِبْرَاهِيْمَوَبَارِكْعَلَىمُحَمَّدٍوَعَلَىآلِمُحَمَّدٍكَمَابَارَكْتَعَلَىآلِإِبْرَاهِيْمَفِيالْعَالَمِيْنَإِنَّكَحَمِيْدٌمَجِيْدٌ» and as for the way of greeting (salaam), you already know it.”
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1380