Sunan at-Tirmithiy كتاب الدعوات باب ما جاء أن دعوة المسلم مستجابة

حَدَّثَنَا يَحْيَى بْنُ حَبِيبِ بْنِ عَرَبِىٍّ حَدَّثَنَا مُوسَى بْنُ إِبْرَاهِيمَ بْنِ كَثِيرٍ الأَنْصَارِىُّ قَالَ سَمِعْتُ طَلْحَةَ بْنَ خِرَاشٍ قَالَ سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللَّهِ رضى الله عنهما يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ أَفْضَلُ الذِّكْرِ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَفْضَلُ الدُّعَاءِ الْحَمْدُ لِلَّهِ. قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ غَرِيبٌ لاَ نَعْرِفُهُ إِلاَّ مِنْ حَدِيثِ مُوسَى بْنِ إِبْرَاهِيمَ. وَقَدْ رَوَى عَلِىُّ بْنُ الْمَدِينِىِّ وَغَيْرُ وَاحِدٍ عَنْ مُوسَى بْنِ إِبْرَاهِيمَ هَذَا الْحَدِيثَ.
The Messenger of God, peace and blessings of God be upon him, said, "The best remembrance [of God] (1) is to say, 'there is no god except Allāh (2)' and the best supplication is, 'Praise is to God.'" Footnotes: (1) A devotional practice that focuses on feeling God’s presence in the different facets of life. It includes several kinds like practical remembrance (obeying God’s commandments), verbal remembrance (supplications, praising, glorifying and exalting God), and remembrance by the heart (meditation). (2) Allāh is the Arabic name for the One and Only God, the same God shared by all monotheistic faiths (the name Allāh is often used by Arabic-speaking Christians and Jews). The name Allāh encompasses all the divine names and attributes of the Lord of the worlds, and hence has vast scopes of meaning. It is for this reason that Muslims consider it unique. Unlike the word 'God', Allāh in Arabic has no inflections of gender or number. Click on ḥadīth to read more