The reading of Shema Yisrael שמע ישראל prayer, in the morning and in the evening is a tool, which is like a sword that can never be defeated.
Like in the physical dimension we have enemies that come to destroy us, so in the spiritual dimension.
In the upper worlds there is a need for kind of judgements to remove the forces that are coming from out of the system (סיטרא אחרה ) of the Tree of Life. They tries to destroy the sources of energy and beneficent to the lower worlds.
One of the tools is the sword, and its essence and power to remove the negativity comes from the Torah.
The prayer of Shema with 248 words , 1000 letters, 4 sections for the Tetragramaton, is like a sword in the hand on the person and it help him in the morning to stop the master of negativity from entering his day. At night it protects his soul from the negativity while the soul ascends for the night rest above.
The tongue, shaped like a sword, is the two way sword that control the type of energy around our soul. The Holy Ari said in “The Gates of the Holy Spirit”, that every word we say creates angels. Positive or negative based of its essence.
Watch your words and you control the negativity around you.
When scanning the Zohar, the soul is empowered with pure Light energy and it helps a person bring out words of positive and it protects him.
מקור הקטע: הקדמת תיקוני הזוהר עם פרוש מעלות הסולם (רבי יהודה צבי ברנדויין זל) פסקה 181