Hadith on Dua: Door of mercy for those who supplicate

Ibn Umar reported: The Messenger of Allah, peace and blessings be upon him, said, “Whoever among you opens the door of supplication, the door of mercy is opened for him. Allah is not asked for anything more beloved to him than to be asked for wellness. Supplication benefits by what is sent down and what is not sent down. O servants of Allah, you must supplicate.”

Source: Sunan al-Tirmidhī 3548

Grade: Hasan (fair) according to Al-Albani

عَنْ ابْنِ عُمَرَ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ فُتِحَ لَهُ مِنْكُمْ بَابُ الدُّعَاءِ فُتِحَتْ لَهُ أَبْوَابُ الرَّحْمَةِ وَمَا سُئِلَ اللَّهُ شَيْئًا يَعْنِي أَحَبَّ إِلَيْهِ مِنْ أَنْ يُسْأَلَ الْعَافِيَةَ إِنَّ الدُّعَاءَ يَنْفَعُ مِمَّا نَزَلَ وَمِمَّا لَمْ يَنْزِلْ فَعَلَيْكُمْ عِبَادَ اللَّهِ بِالدُّعَاءِ

3548 سنن الترمذي كتاب الدعوات باب في دعاء النبي صلى الله عليه وسلم

3409 المحدث الألباني خلاصة حكم المحدث حسن في صحيح الجامع