Abu Hurayra reported that the Prophet, may Allah bless him and grant him peace, said, "Nothing is dearer to Allah than supplication."  

عَنِ النَّبِيِّ ﷺ قَالَ لَيْسَ شَيْءٌ أَكْرَمَ عَلَى اللهِ مِنَ الدُّعَاءِ  

Abu Hurayra reported that the Prophet, may Allah bless him and grant him peace, said, "The noblest act of worship is supplication."  

عَنِ النَّبِيِّ ﷺ قَالَ أَشْرَفُ الْعِبَادَةِ الدُّعَاءُ  

An-Nu'man ibn Bashir reported that the Prophet, may Allah bless him and grant him peace, said, "Supplication is worship.' Then he recited, 'Call on Me and I will answer you.'"  

عَنِ النَّبِيِّ ﷺ قَالَ إِنَّ الدُّعَاءَ هُوَ الْعِبَادَةُ ثُمَّ قَرَأَ {ادْعُونِي أَسْتَجِبْ لَكُمْ}  

'A'isha said, "The Prophet, may Allah bless him and grant him peace, was asked, 'Which type of worship is best?' He replied, 'A man's supplication for himself.'"  

عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ سُئِلَ النَّبِيُّ ﷺ أَيُّ الْعِبَادَةِ أَفْضَلُ؟ قَالَ دُعَاءُ الْمَرْءِ لِنَفْسِهِ  

Maqil bin Yasar (ra) said that he came to the Prophet (ﷺ) with Abu Bakr (ra). He said, "O Abu Bakr, polytheism enters your people more quietly (secretly) than the movement of ants." Abu Bakr asked, "Is there a kind of polytheism besides associating anything with Allah?" The Prophet (ﷺ) said," By him who has my life in his power, polytheism is more concealed than the movement of ants. Shall I not teach you something which if you say will eliminate minor or major (polytheism)?" He then said, "Say `O Allah! I seek refuge in you lest I associate anything with you while I know it, and I seek your forgiveness for what I do not know.’"  

سَمِعْتُ مَعْقِلَ بْنَ يَسَارٍ يَقُولُ انْطَلَقْتُ مَعَ أَبِي بَكْرٍ الصِّدِّيقِ رَضِيَ اللَّهُ عَنْهُ إِلَى النَّبِيِّ ﷺ فَقَالَ يَا أَبَا بَكْرٍ لَلشِّرْكُ فِيكُمْ أَخْفَى مِنْ دَبِيبِ النَّمْلِ فَقَالَ أَبُو بَكْرٍ وَهَلِ الشِّرْكُ إِلاَّ مَنْ جَعَلَ مَعَ اللهِ إِلَهًا آخَرَ؟ فَقَالَ النَّبِيُّ ﷺ وَالَّذِي نَفْسِي بِيَدِهِ لَلشِّرْكُ أَخْفَى مِنْ دَبِيبِ النَّمْلِ أَلاَ أَدُلُّكَ عَلَى شَيْءٍ إِذَا قُلْتَهُ ذَهَبَ عَنْكَ قَلِيلُهُ وَكَثِيرُهُ؟ قَالَ قُلِ اللَّهُمَّ إِنِّي أَعُوذُ بِكَ أَنْ أُشْرِكَ بِكَ وَأَنَا أَعْلَمُ وَأَسْتَغْفِرُكَ لِمَا لا أَعْلَمُ