The word Jawshan literally means breastplate, chain mail, or a similar type of armor. In religious terminology, it denotes a long prayer, known as al-Jawshan al-Kabir, transmitted from the Prophet.

Musa al-Kazim relates al-Jawshan al-Kabir from the Prophet on the successive authority of Ja'far al-Sadiq, Muhammad al-Bakir, Zayn al-Abidin, Husayn, and the fourth caliph Ali.

Al-Jawshan al-Kabir is a long prayer consisting of one hundred chapters. All chapters, except a few, consist of ten of God's names and attributes. At the end of each chapter, this passage is repeated: Glory be to You, O Lord! There is no god, but You! We beg for mercy, protect us from Hell!

At the beginning of twenty-five of these one hundred chapters, the phrase O God! I ask from You and beseech through Your beautiful names is found and these chapters contain the names of God invocated, such as "O God, O All-Merciful, O All-Compassionate." Within every chapter that begins with this phrase, there are various supplications beginning with expressions such as "O the best of forgivers." Thus, the whole prayer comprises two-hundred-and-fifty names of God and seven-hundred-and-fifty attributes and supplications.

The main purpose of all these supplications is—as is clearly understood from the content of the prayer and from the phrase We beg for mercy, protect us from Hell! repeated at the end of each chapter—to plead salvation from misfortune during this life and from punishment in the Hereafter.

Al-Jawshan al-Kabir is one of the prayers most frequently recited by Muslims; its contents have deep meanings, its expressions are elegant, and various hadiths reported from the Prophet relate the rewards that one may receive in this world as well as in the hereafter for reciting it. Ahmed Ziyaeddin Gümüşhanevi included this prayer in his Majmû'atü'l-Ahdhâb, in which he collected many prayers that were repeatedly recited and formulas of remembrance of God. Later on, this prayer was published many times in separate volumes. In more recent times, it was made popular by Bediüzzaman Said Nursi (1877-1960), the author of the modern Qur'anic commentary the Risale-i Nur.