As reported in the journal Frontiers of Psychology researchers in Sweden (the tribe of Naphtali) have found that choir singers not only harmonise their voices, they also synchronise their heart rates.
It is believed that the synchrony occurs because the singers coordinate their breathing. The more structured the song the more the heart rates synchronised.
Therefore, as the choir (nation) sings (expresses) the structured song (the Law) the heart rates are (the purpose is) synchronised by the action of breathing (prayer).
