This is narrated by Arjuna to Yudhishthira in his attempt to convert the latter from taking up asceticism after winning back the kingdom through a great war (Shanti Parva)
The glory of Domesticity over Asceticism: Conversation between Indra and ascetics
A number of well-born Brahmana youth of little understanding, without the hirsute honours of manhood, abandoning their homes, came to the woods for leading a forest life. Regarding that to be virtue, those youths of abundant resources became desirous of living as Brahmacharins, having abandoned their brothers and sires. It so happened that Indra became compassionate towards them. Assuming the form of a golden bird, the holy Sakra addressed them, saying: “That at which is done by persons that eat the remnants of a sacrifice is the most difficult of acts that men can achieve. Such an act is highly meritorious. The lives of such men are worthy of every praise. Having attained the object of life, those men, devoted to virtue obtain the highest end.”
Hearing these words, the Rishis said: “Lo! This bird applauds those that subsist upon the remnants of sacrifices. He informs us of it, for we live upon such remnants.”
The bird then said: “I do not applaud you. You are stationed with mire and very impure. Living upon offals, you are wicked. You are not persons subsisting upon the remnants of sacrifice.”
The Rishis said: “We regard this our course of life to be highly blessed. O bird! Tell us, what is for our good. Your words inspire us with great faith.”
The bird said: “If you do not refuse me your faith by arraying yourselves against your better selves, then I shall tell you words that are true and beneficial.”
The Rishis said: “We shall listen to your words, for the different paths are all known to you. We desire also to obey your commands. Instruct us now.”
The bird said: “Among quadrupeds the cow is the foremost. Of metals, gold is the foremost. Of words, mantras, and of bipeds, the Brahmanas, are the foremost. These mantras regulate all the rites of a Brahmana's life beginning with those appertaining to birth and the period after it, and ending with those appertaining to death and the crematorium. These Vedic rites are his heaven, path, and foremost of sacrifices. If it were otherwise, how could I find the acts of persons in quest of heaven become successful through mantras? He who, in this world, adores his soul, firmly regarding it to be a deity of a particular kind, obtains success consistent with the nature of that particular deity. The seasons measured by half the months lead to the Sun, the Moon, or the Stars. These three kinds of success, depending upon action are desired by every creature. The domestic mode of life is very superior and sacred and is called the field for the cultivation of success. By what path do those men go that censure action? Of little understanding and deprived of wealth, they incur sin. And since those men of little understanding live by abandoning the eternal paths of the gods, the paths of the Rishis, and the paths of Brahma, therefore, they attain to paths disapproved of by the Shrutis.
“There is an ordinance in the mantras which says, “You sacrificer! Perform the sacrifice represented by gifts of valuable things. I will give you happiness represented by sons, animals, and heaven!” To live, therefore, in accordance with ordinance is said to be the highest asceticism of the ascetics. Therefore, you should perform such sacrifices and such penances in the shape of gifts. The due performance of these eternal duties, the worship of the gods, the study of the Vedas, and the gratification of the Pitris, as also regardful services unto the preceptors, these are called the austerest of penances. The gods, by performing such exceedingly difficult penances, have obtained the highest glory and power. I, therefore, tell you to bear the very heavy burden of the duties of domesticity. Without doubt, penances are the foremost of all things and are the root of all creatures. Asceticism, however, is to be obtained by leading a life of domesticity, upon which depends everything. They that eat the remnants of feasts, after duly apportioning the food morning and evening among kinsmen, attain to ends that are exceedingly difficult of attainment. They are called eater of the remnants of feasts who eat after having served guests and gods and Rishis and kinsmen. Therefore, those persons that are observant of their own duties, that practise excellent vows and are truthful in speech, become objects of great respect in the world, with their own faith exceedingly strengthened. Free from pride, those achievers of the most difficult feats attain to heaven and live for unending time in the regions of Sakra.”
Those ascetics then, hearing these words that were beneficial and fraught with righteousness, abandoned the Dharma of renunciation, saying, “There is nothing in it,” and betook themselves to a life of domesticity.