The Messenger of Allah ﷺ said, "Three supplications are answered without any doubt: the supplication of the oppressed, the supplication of the traveler, and the supplication of a parent against their child."
حدثنا علي بن حجر أخبرنا إسمعيل بن إبراهيم عن هشام الدستوائي عن يحيى بن أبي كثير عن أبي جعفر
قال رسول الله ﷺ ثلاث دعوات مستجابات لا شك فيهن دعوة المظلوم ودعوة المسافر ودعوة الوالد على ولده
[Hasan]. Abu Dawud also reported it in the book of Witr, chapter on supplicating in someone's absence, no. 1536, and Ibn Majah, no. 3862, from the hadith of Hisham Dastawai with the same chain, and Ibn Hibban graded it sahih, no. 2406. The hadith has many corroborating narrations in Hakim, 1/417, 418, and Haythami's Majma al-Zawaid, 10/151, and elsewhere.