This mantra opens the Katha Upanishad. These are the teachings about death as taught to the most unlikely of students, a teenage boy named Nachiketa.

Om saha naa va-vatu
saha-nau bhun-ak-tu
saha veer-yum kerava-va-hay
tejas vi nava-dahee tamas-tu
ma vid-visha-va-hay.
Om shanti, shanti, shantihi.

Om.
May we be protected
May we enjoy each other
May we work together vigorously
May our study be illuminating
May we not quarrel.
Om, peace, peace, peace.