हरे राम हरे राम राम राम हरे हरे । हरे कृष्ण हरे कृष्ण कृष्ण कृष्ण हरे हरे ॥
Krishna and Rama
Hare Krishna Maha Mantra
A sixteen word mantra of the names Hare, Rama and Krishna, found in the Kali Santarana Upanishad, which calls it the remedy for the faults of the Kali age. In this Upanishad the lines of Hare Rama come first; the Gaudiya Vaishnava tradition of Chaitanya Mahaprabhu chants the Hare Krishna lines first. It is sung as kirtan and counted on a mala of 108 beads, commonly 16 rounds a day.
Wording checked against: Sanskrit Wikisource: कलिसन्तरणोपनिषत् (Kali Santarana Upanishad) https://sa.wikisource.org/wiki/कलिसन्तरणोपनिषत्; Wikipedia: Hare Krishna (mantra) and Kali Santarana Upanishad, for the sixteen word form https://en.wikipedia.org/wiki/Hare_Krishna_(mantra). Editions differ slightly; follow your family's or guru's version if it differs.