Mbh 13.81.3d

Brahmanas of righteous deeds, who have been cleansed by knowledge, study of the Vedas, and observance of vows, should, only in the midst of sacred fires or kine or assemblies of Brahmanas, impart unto their disciples a knowledge of the Gomati Mantras which are every way like unto a sacrifice (for the merit they produce). One should observe a fast for three nights for receiving the boon constituted by a knowledge of the import of the Gomati Mantras. The man who is desirous of obtaining a son may obtain one by adoring these Mantras. He who desires the possession of wealth may have his desire gratified by adoring these Mantras. The girl desirous of having a good husband may have her wish fulfilled by the same means. In fact, one may acquire the fruition of every wish one may cherish, by adoring these sacred Mantras. When kine are gratified with the service one renders them, they are, without doubt, capable of granting the fruition of every wish. Even so, kine are highly blessed. They are the essential requisites of sacrifices. They are grantors of every wish. Know that there is nothing superior to kine.'"