Why is the Abrahamic Prayer considered the best form of prayer upon the Prophet outside of ritual prayer, despite its omission of "peace" (salaam), while Allah Almighty says: "Send your Salaah on him and greet him with Tasleem"? Is it inclusive of the meaning of "peace"? And is the formulation "Allahumma salli wa sallim wa barik ala Muhammad wa ala ali Muhammad" correct outside of ritual prayer?

Prayers upon the Prophet, peace and blessings be upon him, are permissible outside of prayer, using any wording that conveys the meaning. However, within prayer, the reported (ma'thur) form is preferable. The best forms are the Abrahamic prayers (Salat al-Ibrahimiyyah) which the Prophet, peace and blessings be upon him, taught his companions. The Abrahamic prayer is comprehensive, encompassing blessings, grace, and the mention of his family and Abraham, peace be upon him. The meaning of praying upon the Prophet, peace and blessings be upon him, according to the majority of scholars, is mercy from Allah, supplication for forgiveness from the angels, and prayer from human beings. While others hold that it is praise from Allah upon him in the High Assembly. As for salutations (salam), it is a supplication for safety from all afflictions and terrors, and for the safety of his law and his Sunnah.