ॐ द्यौः शान्तिरन्तरिक्षं शान्तिः पृथिवी शान्तिरापः शान्तिरोषधयः शान्तिः । वनस्पतयः शान्तिर्विश्वेदेवाः शान्तिर्ब्रह्म शान्तिः सर्वं शान्तिः शान्तिरेव शान्तिः सा मा शान्तिरेधि ॥ ॐ शान्तिः शान्तिः शान्तिः ॥
Peace for all realms
Shanti Path (Om Dyauh Shantih)
The great peace chant of the Shukla Yajurveda (Vajasaneyi Samhita 36.17). It invokes peace in the sky, the atmosphere, the earth, the waters, plants, trees, all the gods and Brahman, and asks that this very peace come to me. It is recited at the end of havans, pujas and ceremonies, and the last line repeats Shantih three times.
Wording checked against: Sanskrit Wikisource: शुक्लयजुर्वेदः अध्यायः ३६, verse 36.17 (text and commentary edition) https://sa.wikisource.org/wiki/शुक्लयजुर्वेदः/अध्यायः_३६. Editions differ slightly; follow your family's or guru's version if it differs.