What are six syllables of Truth and their functions?

The six syllables of Truth or Six-syllable Mantra of Great Illumination

from the Buddhist esoteric school are om mani padme hum. The

mantra is to be chanted without having to unravel its mystery. The

chanter focuses in mind, congeals and gathers thinking, allows

differentiation and false thoughts to arise no more, and reaches the

goal of samadhi.

The six syllables of Truth together, as expounded, are about shiny

pearl and blooming lotus, and reciting them effectuates concentration

of resolve. Atop that, reciting the six syllables of Truth—like namo

Amitabha, which Pureland sect practitioners hold to and chant—

effectuates purification of own faculty of mind and produces stellar

results in the pursuit of Pureland rebirth.