اصول اربعه یا کتب اربعه نام چهار مجموعه کتاب حدیثی است که از پراهمیت ترین کتابهای حدیثی نزد شیعه محسوب میشود.
به دلیل درهمآمیختگی احادیث صحیح و جعلی اسلامی، سه تن از بزرگان شیعه، اقدام به گردآوری و نوشتن چهار مجموعه کتاب روایی کردند که به کتب اربعه معروف هستند و مؤلفان آنها را محمدین ثلاثه اول مینامند؛ زیرا اسامی هر سه محمد و کنیه هر سه ابوجعفر بودهاست. این کتابها عبارتاند از:
The Four Books have been praised by many notable Shi'a scholars. This is what some have said:
Shaikh al-Hur al-Aamili said, "The authors of the 4 Books of shia have testified that the Hadiths of their books are accurate (saheeh) , firm and well conducted from the roots that all shia agreed on , and if you consider those scholars (the authors of the four books) are reliable then you must accept their sayings and their narrations . " [Al-wasa’el, vol. 20, p. 104]
Abd al-Husayn Sharaf al-Din al-Musawi said: "Al-Kafi, Al-Istibsaar, Al-Tahzeeb and Mun La Yahduruhu Al-faqeeh are Mutawatirah and agreed on the accuracy of its contents (the Hadiths), and Al-Kafi is the oldest, greatest, best and the most accurate one of them.“ [The book of Al-Muraja'aat (A Shi'i-Sunni dialogue), Muraj'ah No. 110]
Al-Tabrosi (aka, Tabarsi) said:"Al-Kafi among the 4 shia books is like the sun among the stars, and who looked fairly would not need to notice the position of the men in the chain of hadiths in this Book, and if you looked fairly you would feel satisfied and sure that the hadiths are firm and accurate."[Mustadrak al-Wasail, vol. 3, p. 532]