عن عمر بن الخطاب قال: إن الدعاء موقوف بين السماء والأرض لا يصعد منه شيء حتى تصلي على نبيك صلى الله عليه وسلم (سنن الترمذي رقم 486)

Hazrat ‘Umar (radhiyallahu ‘anhu) narrates, “Du‘aas remain suspended between the heavens and the Earth. They do not proceed towards the heavens as long as Durood on Nabi (sallallahu ‘alaihi wasallam) has not been recited (i.e. there is no guarantee for their acceptance).”