צור ילדתך תשי (האזינו לב:יח)

The word תש”י is the acronym for the following three terms: תורה שמע יום-המיתה.  The passuk mentions three things that serve as spiritual ammunition to conquer the Yetzer Hara (evil inclination) and not to forget Hashem’s presence.  As Chazal says: “לעולם ירגיז אדם יצר טוב על יצר הרע ויעסוק בתורה ואם לא נצחו יקרא קריאת שמע, ואם לא נצחו יזכיר לו יום המיתה” – if a person wants his Yetzer Tov to prevail over his Yetzer Hara, he should learn Torah and if that does not help he should recite the Shema and if that does not succeed, then he should remind himself of the day of his death, which will undoubtedly jolt him to overpower his Yetzer Hora.