YV 1.5b

Agni went away from the gods, he entered the reed; he resorted to the hole which is formed by the perforation of the reed; the spade is perforated to make it his birthplace; wherever he lived, that became black; (the spade) is stained, for perfection of form; it is pointed at both ends, for the winning of light both hence and from yonder world; it is a fathom long; so much is the strength in man; (verily it is) commensurate with his strength; it is unlimited in girth, to win what is unlimited; that tree which has fruit is strong among trees, the reed bears fruit, (the spade) is of reed, to win strength. That part of the sacrifice is unsuccessful which is performed with no Yajus. 'This bond of order they grasped', (with these words) he takes up the horse's halter, to make a Yajus and to make successful the sacrifice. 'Swiftly run hither, O steed', (with these words) he halters the horse; verily he proclaims its greatness in this form. 'Yoke ye the ass', (with these words) (he halters) the ass; verily he establishes the ass on the nonexistent; therefore the ass is less real than the horse. 'In each need more strong', he says [1]; verily in each need he yokes him; 'in each contest we invoke', he says; the contest is food; verily he wins food. 'As friends, Indra to aid us', he says; verily he wins power. Agni went away from the gods, him Prajapati found; the horse is connected with Prajapati, with the horse he collects (it), for the finding (of Agni). Now confusion occurs in that they perform the same thing with a better and worse (instrument), for the ass is worse than the horse [2]; they lead the horse in front to avoid confusion; therefore the worse follows after the better.