(17) بَابُ دَعْوَةِ الْوَالِدَيْنِ
Abu Hurayra reported that the Prophet, may Allah bless him and granthim peace, said, "Three supplications are answered without a doubt:
thesupplication of someone who is oppressed, the supplication of someone ona journey, and the supplication of parents for their children."
Reference: Al-Adab Al-Mufrad 32
In-book reference: Book 1, Hadith 32
English translation: Book 1, Hadith 32