The Messenger of Allah ﷺ said, "Fasting is a shield."
قال رسول الله ﷺ: الصيام جنة.
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Muslim narrated it in the Book of Fasting (1151:162) through various routes from Mughira (that is, Hazami), from Abu Zinad, from Araj, from Abu Hurairah, as mentioned.The two sheikhs, Bukhari (1904) and Muslim (1151:162), both narrated it through the route of Ibn Jurayj, who said, Ata told me, from Abu Salih Zayyat, that he heard Abu Hurairah, as mentioned, in a long hadith.The word "junnah" (with damma on the jim) means a shield and protection, from sins in this world and from the Fire in the hereafter.