Mishkat al-Masabih 9 Supplications كتاب الدعوات 26

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: ” ثَلَاثُ دَعَوَاتٍ مُسْتَجَابَاتٍ لَا شَكَّ فِيهِنَّ: دَعْوَةُ الْوَالِدِ وَدَعْوَةُ الْمُسَافِرِ وَدَعْوَةُ الْمَظْلُومِ ” . رَوَاهُ التِّرْمِذِيُّ وَأَبُو دَاوُدَ وَابْنُ مَاجَهْ

He reported God’s messenger as saying, “Three supplications are answered, there being no doubt about them: that of a parent, that of a traveller, and that of one who has been wronged.” Tirmidhi, Abu Dawud and Ibn Majah transmitted it.