حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا هِشَامٌ الدَّسْتَوَائِيُّ، عَنْ يَحْيَى، عَنْ أَبِي جَعْفَرٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ ‏"‏ ثَلاَثُ دَعَوَاتٍ مُسْتَجَابَاتٌ لاَ شَكَّ فِيهِنَّ دَعْوَةُ الْوَالِدِ وَدَعْوَةُ الْمُسَافِرِ وَدَعْوَةُ الْمَظْلُومِ ‏"‏ ‏.‏

Narrated AbuHurayrah: The Prophet (PBUH) said: Three supplications are answered, there being no doubt about them; that of a father, that of a traveller and that of one who has been wronged. Translation Not Available

Book Ref: Sunan Abi Dawud Book 8 Hadith 1536
Web Ref:  Sunan Abi Dawud Book 8 Hadith 1531