ॐ सह नाववतु सह नौ भुनक्तु । सह वीर्यं करवावहै । तेजस्विनावधीतमस्तु मा विद्विषावहै ॥ ॐ शान्तिः शान्तिः शान्तिः ॥
Shanti (peace), teacher and student
Om Saha Navavatu
A peace invocation said by teacher and student together before study. It asks that both be protected and nourished, that they work with strength, that their learning be bright, and that no hatred arise between them. It appears at the start and end of the Taittiriya Upanishad (Brahmavalli) and of the Katha Upanishad in the Krishna Yajurveda tradition, and in the Narayana Upanishad. It is recited at the opening of classes and lessons.
Wording checked against: Sanskrit Documents: Narayanopanishat (shanti mantra at the start and end) https://sanskritdocuments.org/doc_upanishhat/nArAyaNopaniShat.html; Greenmesg: Om Sahana Vavatu https://greenmesg.org/stotras/vedas/om_sahana_vavatu.php; Shlokam.org: Sahana Vavatu https://shlokam.org/sahanavavatu/. Editions differ slightly; follow your family's or guru's version if it differs.