Cundī dhāraṇī or mantra also to start with appeared inside the Kāraṇḍavyūhasūtra: namaḥ saptānāṃ samyaksaṃbuddha koṭīnāṃ tadyathā oṃ cale cule cunde svāhā The use of mantra or the repetition of particular phrases in Pali is a highly popular sort of meditation while in the Theravada tradition. Easy mantras use repetition https://www.youtube.com/@Mahavidyabaglamukhi/