Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
ahmad-zuhd:872ʿAbdullāh from my father > Abū Muʿāwiyah > al-Aʿmash > Mālik

[Machine] "Do you not see the abundance of people's prayers and the scarcity of their answers? And do they not know why that is? That is nothing but because Allah does not accept except the sincere prayer. Abdul Rahman ibn Yazid said while sitting with them, 'If he says that, then Abdullah has indeed said that Allah does not hear from a complainer, nor from a joker, nor from a desirer, nor from a caller except a sincere prayer from his heart.'"  

الزهد لأحمد:٨٧٢حَدَّثَنَا عَبْدُ اللَّهِ حَدَّثَنَا أَبِي حَدَّثَنَا أَبُو مُعَاوِيَةَ حَدَّثَنَا الْأَعْمَشُ عَنْ مَالِكٍ قَالَ كَانَ الرَّبِيعُ بْنُ خُثَيْمٍ يَأْتِي عَلْقَمَةَ يَوْمَ الْجُمْعَةِ فَيَتَحَدَّثُ إِلَيْهِ فَأَتَاهُ ذَاتَ يَوْمٍ فَقَالَ أَلَا تَعْجَبُ دَخَلَ عَلَيَّ رَجُلٌ مِنْ أَهْلِ الْكِتَابِ؟ فَقَالَ

أَلَا تَرَى إِلَى كَثْرَةِ دُعَاءِ النَّاسِ وَقِلَّةِ الْإِجَابَةِ لَهُمْ؟ وَهَلْ يَدْرُونَ مِمَّ ذَلِكَ؟ وَمَا ذَاكَ إِلَّا أَنَّ اللَّهَ ﷻ لَا يَقْبَلُ إِلَّا الْفَاضِلَ مِنَ الدُّعَاءِ فَقَالَ عَبْدُ الرَّحْمَنِ بْنُ يَزِيدَ وَكَانَ جَالِسًا مَعَهُمْ لَئِنْ قَالَ ذَاكَ لَقَدْ قَالَ عَبْدُ اللَّهِ إِنَّ اللَّهَ لَا يَسْمَعُ مِنْ مُسَمِّعٍ وَلَا مِنْ مُرَاءٍ وَلَا مِنْ لَاعِبٍ وَلَا مِنْ دَاعٍ إِلَّا دَاعٍ دُعَاءً ثَبْتًا مِنْ قَلْبِهِ