The learned know this to be a great principle that Prana and Apana and Udana and Şamana and Vyana are the five sacrificing priests.
प्राणापानावुदानश्च समानो व्यान एव च। पञ्चहोतूंस्तथैतान् वै परं भावं विदुर्बुधाः॥