The following was taken from ath-Thariq Ila Allah al-Munji fi Zaman ad-Dajjal wa al-Mahdi, and interpreted from the Arabic by Ustadz Muhammad ‘Abdullah at-Tijani al-Ibrahimi.
Imam an-Nawawi (r.a.) was once asked, in the masjid of Damascus, “Is the swalawat ‘ala an-Nabi greater in Reward or the obligatory swalah which has been repeatedly Mentioned by Allah?”
Imam an-Nawawi (r.a.) was silent for a moment and then replied, “The swalawat upon the Messenger of Allah (s.a.w.) is greater.”
So, the questioner said, “How can you say that! Did not Allah Make the five daily prayers an obligation on His servants? So how can He Exalt another Command over this one?”
So, Imam an-Nawawi (r.a.) answered, “Yes, He has Ordered the five daily prayers, and He also Made it an obligation to offer prayers of peace and blessings upon the Messenger of Allah (s.w.t.) in His Saying:
Allah, and His angels, Send Blessings on the Prophet: O ye that believe! Send ye blessings on …