What is the supplication one should recite to invoke Allah on behalf of the Prophet Muhammad (pbuh)?
 Narrated Abu Sa`id Al-Khudri:                     We said, "O Allah's Apostle! (We know) this greeting (to you) but how shall we invoke Allah for you?" He said, "Say! Allahumma salli ala Muhammadin `Abdika wa rasulika kama- sallaita 'ala all Ibrahim wa barik ala Muhammadin wa'ala all Muhammadin kama barakta 'ala all Ibrahim.' Al-Laith said: 'Ala Muhammadin wa 'ala all Muhammadin kama barakta ala all Ibrahim.