What is the Hebrew prayer of protection?

Answer 1

There isn't one single Hebrew prayer of protection. There are many prayers that contain requests for protection.

The Bedtime Shma is a good example.

Here is an English translation. The second paragraph talks about protection:

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THE BEDTIME SHMARuler of the universe, I hereby forgive anyone who angered or antagonized me or who sinned against me - whether against my body, my property, my honor or against anything of mine; whether he did so accidentally, willfully, carelessly, or purposely; whether through speech, deed, thought, or notion; whether in this transmigration or another transmigration - I forgive every Jew. May no man be panished because of me. May it will be Your will, HASHEM, my God and the God of my ancestors, that I may make no more mistakes. Whatever mistakes I have made before You, may You blot out in Your abundant mercies, but not through suffering or bad illnesses. May the expressions of my mouth and the thoughts of my heart find favor before You, HASHEM, my Rock and my Redeemer.

HAMAPIL

Blessed are You, HASHEM, our God, KING of the universe, who casts the bonds of sleep upon my eyes and slumber upon my eyelids. May it be Your will, HASHEM, my God and the God of my ancestors, that You lay me down to sleep in peace and rise me erect in peace. May my ideas, bad dreams, and bad notions not confound me; may my offspring be perfect before You, and may You illuminate my eyes lest I die in sleep, Who illuminates the pupil of the eye. Blessed are You, Hashem, Who illuminates the entire world with His glory.

God, trustworthy Sovreign.

[Recite the first verse aloud, with the right hand covering the eyes,

and concentrate intensely upon accepting God's absolute sovereignty.] Hear, O Israel: HASHEM is our God, HASHEM, the One and Only.

In an undertone: Blessed is the Name of Your glorious kingdom for all eternity.

Deuteronomy 6:5-9

You shall love HASHEM, your God, with all your heart, with all your soul and with all your resources. Let these matters that I command you today be upon your heart. Teach them thoroughly to your children and speak of them while you sit in your home, while you walk on the way, when you retire and when you arise. Bind them as a sign upon your arm and let them be tefillin between your eyes. And write them on the doorposts of your house and upon your gates.

May the pleasantness of HASHEM, our God, be upon us - may God establish our handiwork for us; our handiwork may God establish.