Sawm (Fasting) is a shield, as long as he (the fasting person) does not tear it up. [Nasa’ee]

Note: Fasting is a protection from Shaytaan or from Allah’s punishment in the hereafter. One ho indulges in sins while fasting, such as lies, backbiting etc., they become the cause of the fast becoing wasted.

Source: Profit from Ramadhaan by Shaykh Saleem Dhorat