Al-Kāfi
Hadith 16195ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ فَضَّالٍ عَنْ بَعْضِ أَصْحَابِنَا عَنِ الرِّضَا (عَلَيهِ السَّلام) أَنَّهُ كَانَ يَقُولُ لأصْحَابِهِ عَلَيْكُمْ بِسِلاحِ الأنْبِيَاءِ فَقِيلَ وَمَا سِلاحُ الأنْبِيَاءِ قَالَ الدُّعَاءُ.
5. A number of our people have narrated from Ahmad ibn Muhammad from ibn Faddal from certain individuals of our people who has said the following: “Al-Rida (a.s.) would say to his disciples, ‘You must keep with you the weapons of the prophets.’ It was asked, ‘What are the weapons of the prophets?’ The Imam said, ‘It is prayer, pleading before Allah for help.’”