May the Eternal bless you and keep you.
יְבָרֶכְךָ יהוה, וְיִשְׁמְרֶךָ
Yeh-vah-REH-che-cha Adonai v’YISH-meh-reh-chah
May the Eternal cause His face to shed light upon you and be gracious unto you.
יָאֵר יהוה פָּנָיו אֵלֶיךָ, וִיחֻנֶּךָּ
yah-AIR Adonai pan-AV eh-LEHcha vee-choo-NEH-ka)
May the Eternal lift up His face to you and give you peace.
יִשָּׂא יהוה פָּנָיו אֵלֶיךָ, וְיָשֵׂם לְךָ שָׁלוֹם
yee-SA Adonai pah-NAV eh-leh-kha v’yah-SEM leh-KHAH sha-LOM.
This text, from Numbers 6:24-26, is known as the Birkat Kohanim, or priestly blessing. It is one of the most familiar passages of Torah to a synagogue-going Jew. In the synagogue service, traditionally it is pronounced by the adult male kohanim (descendants of Aaron) daily in Israel and on certain days of the year in the Diaspora. (For a video of kohanim giving the blessing at the Western Wall, click this link.)
The priestly blessing is also used for blessings on other occasions. Parents may say it over children on Shabbat evenings, and a chazzan (cantor) or rabbi in the Reform movement may say it on a solemn occasion for blessing, such as a baby naming, a conversion, or a birthday.
It is associated with a hand gesture that is often pictured on the grave markers of kohanim (see photo below).
This text is the content of the oldest Biblical inscription currently known, the Ketef Hinnom inscription, found in 1979 near the Old City of Jerusalem. The words were inscribed in paleo-Hebrew on thin silver strips and rolled into an amulet to be worn on a string around the neck. They are estimated to be from the early 6th century BCE (1st Temple period) based upon analysis of the script.