وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «ادْعُوا اللَّهَ وَأَنْتُمْ مُوقِنُونَ بِالْإِجَابَةِ وَاعْلَمُوا أَنَّ اللَّهَ لَا يَسْتَجِيبُ دُعَاءً مِنْ قَلْبٍ غَافِلٍ لَاهٍ»
He reported God’s messenger as saying, “Supplicate God when you are assured of being answered, and know that God does not answer a supplication which comes from a careless and inattentive heart.”
Mishkat al-Masabih 2144, Book 10, Supplications, Hadith 18. 1 min read