When Firaun was killing the male progeny of Bani
Israel and burying their women and they were put
under severe troubles, Allah ordered Hazrat Moosa
(a.s.) to inform the Bani Israel that before commencing
any work they should recite salawaat on Mohammad
(s.a.w.a.) and his progeny. When they commenced their
works with salawaat, their works were completed easily
and when they forsake reciting salwaat they were
involved in difficulties
The women of Bani Israel due to the fear of Firaun had
left their children in the desert after reciting ten
salawaat on Mohammad (s.a.w.a.) and his progeny.
Allah, the High appointed an angel to take care of them.
He made milk to flow from one finger and food from
another till they grew.
When Firaun abducted a few of the women folk of Bani
Israel, the family members of the women came to
Hazrat Moosa (a.s.) and apprised him about it. Hazrat
Moosa (a.s.) prayed to Allah and he (a.s.) was informed
that when the women see Firaun or his men they should
recite salawaat. Due to this they were saved from their
evils
Ref : Fazila e Salawaat