Since the Ṛgvedic (Rigvedic) period, Indian culture has conceived of the guest (atithi) as one who must be treated with respectful and humble hospitality and offered food and shelter. The host should do everything within his power to please the guest. Any yajña (yajna) would require fire (agni; imagined as the Fire-god), therefore fire has been hailed as the dearest of man’s guests – priyo viśām atithirmānuṣīm. If the offerings made to the fire is seen as reception of this dearest guest of man, we can imagine on how high an altar the ancient Indian culture placed the guest, and how important it was to receive the guest with proper courtesy and honour. 

The first worship of or offerings made to Sūrya (Surya), the Sun-god, in the morning has been called ātithya (atithya) or ‘reception’. The name signifies the deep thought that the Sun must be offered gifts (a token of hospitality) and welcomed as an honourable guest before he starts his journey of the day around the globe. 

During the era of composition of the Brāhmaṇa (Brahmana) texts having one’s own lunch or dinner before the others of the household have finished theirs was considered a gesture of disrespect. This is the originating point of the entire concept of atithi and associated ideas. Śatapatha Brāhmaṇa (Satapatha Brahmana) exclaims, if feeding oneself before feeding the others of the household itself happens to be an abominable act, what can be said of those who eat even before performing rituals and yajña for the gods (which are considered as offering food to the gods)! 

Kaṭhopaniṣada (Kathopanishada) observes that a brāhmaṇa arriving as a guest is like fire – he has to be appeased with water (for washing his feet) and other offerings. Kaṭhopaniṣada also discusses the virtues one fails to acquire if he keeps a guest unfed. 

The later ages saw not only brāhmaṇa but people from all other castes also becoming as reverent as brāhmaṇa when they appear as guests. This must be taken as a liberal gesture on the part of the ancient Brahminic society. Since the age of Śatapatha Brāhmaṇa the society was familiar with the ritual of pañca mahāyajña (pancha mahayajna; five principal yajña) which was mandatory to be observed by every householder. These five principal yajña are namely bhūtayajña (bhutayajna), manuṣyayajña (manushyayajna), pitṛyajña (pitriyajna), devayajña (devayajna) and brahmayajña (brahmayajna). 

Of these, manuṣyayajña bears the significance of treating guests with honour. A pedestrian explanation of the term manuṣyayajña is the daily observable rituals or duties towards manuṣya (manushya) or man. Although the annotating scholars who follow the traditional Brahminical school of thoughts explain the term manuṣya specifically as men belonging to the caste of brāhmaṇa, later the term came to acquire the glory of including people from all strata of human society.  Āpastmba Dharmasūtra (Apastamba Dharmasutra) identifies the act of doing one’s best to feed people itself as manuṣyayajña – manuṣyebhyo yathāśakti dānam.

Later scriptures, keeping the said explanation by the authors of Śatapatha Brāhmaṇa and Dharmasūtra, identified manuṣyayajña or nṛyajña (nriyajna; nṛ being a Sanskrit synonym of ‘man’) directly as serving the guest – nṛyajño’tithipūjanam. 

Yāska (Yaska), the author of the Vedic encyclopaedia Nirukta, while discussing one particular hymn of Ṛgveda (Rigveda) 

athithiḥ abhyatito gṛhān bhavati
abhyati tithiṣu parakulāni iti vā. 

Manusaṃhitā (Manusamhita) attempts to define atithi as the brāhmaṇa who stays at another’s house only for a night –

ekarātrantu nivasannatithirbrāhmaṇaḥ smṛtaḥ
anityaṃ hi sthito yasmāt tasmādatithirucyate. 

The Sanskrit root at refers to being constantly on the move and never settling down at a place; from this root at the word atithi originates. Atithi is not merely a guest, but the one who arrives without prior intimation, observing no particular or suitable date for his arrival, and leaves the host’s house after spending only a night fits the definition of atithi.

Śrīdharasvāmī (Sridharaswami) defines atithi as an unknown guest. An extension of this definition would be a person taking refuge in a household where he is totally a stranger. Purāṇas (Puranas) discuss the characteristics of such guests or atithi in detail. Atithi is a non-relative to the host, a person about whose identity nothing is known to the host, arriving to the host’s threshold from a different land with hunger in his stomach and not a penny in his pocket –

akiñcanamasambandhamanyadeśāt samāgatam.

Taittirīya Upaniṣada (Taittiriya Upanishada) teaches to revere the guest as a manifestation of god – atithi devo bhava. 

The humanism of the ancient Aryan society of India inspired the people to treat the penniless, hungry stranger arriving at one’s doorstep as respectfully as one shows to one’s parents or teacher – it became one of the basic principles of their life. So that this lesson of life is not lost along with time, the ancient forefathers transformed it into commandments in the Upanishadic texts and handed them over to the next generations. That is why we find later Purāṇas speaking of the guest in terms of gods and discussing in detail the best ways to treat a guest. Everyday the head of a household should wait for a visitor or guest to arrive. If someone does arrive as guest, the head of the household must not ask his name, identity or any other credentials, and should worship him as respectfully as god and accordingly extend hospitality to the guest.

Although initially the castes of Indian social system played no part in extending respectful hospitality to a guest, later the structure of the Brahminical society gradually injected the hierarchical thoughts associated with casteism in respect to welcoming a guest. Still, whatever caste might the guest belong to, it is believed to be a dharma of the common Indian man to humbly and respectfully offer the guest a seat and water to quench his thirst, to speak to him only with sweet words, to arrange for his food as best as the host can do and provide him with shelter for at least one night. 

The apparently bare dicta of being generous and benevolent to the guest find unique sensitive dimensions in Mahābhārata (Mahabharata). The most important point in this regard is that this epic always emphasises on being charitable to a penniless guest in real need of a shelter than being generous to a guest who already is possessor of substantial wealth –

ko guṇo bharataśreṣṭha samṛddheṣvabhivarṣitam.

Mahābhārata, citing the example of a tree which stretches its shade even over them who come at its root with the intention of cutting it down, opines that even the enemy deserves to be welcomed with utmost honour and the best of one’s means if he arrives as guest. 

At many places in Mahābhārata it has been told that serving and pleasing the guest is one of the holiest things one can do in life and that it earns the host an infinite stretch of stay in heaven in the afterlife. Many stories in the epic also record how far one’s sacrifice could go when his guest’s pleasure was associated. A few examples should suffice to portray how important it was in those days to please the guest with the best possible hospitality.

Once a hungry brāhmaṇa arrived at the doorstep of the sagely king Auśīnara Śivi (Ausinara Sivi) and asked for food. Śivi humbly asked his guest what he wished to have for food, to which the brāhmaṇa replied, “I want to eat the cooked meat of your son Bṛhadgarbha (Brihadgarbha)”. Without being touched by grief, Śivi fulfilled this monstrous desire of his guest. 

After completion of Yudhiṣṭhira’s (Yudhishthira) aśvamedhayajña (ashwamendhayajna; a massive yajña consisting of sacrifice of a chosen horse through which the performer king would have to conquer all the known kingdoms first and establish himself as an emperor thereby), people surrounding him started praising him and the yajña profusely. They said that his charity in this yajña had been incomparable and his grand treatment of the guests to this occasion unprecedented in history. Right at that moment a mongoose, half of its body golden, entered the arena where Yudhiṣṭhira was holding court. Addressing Yudhiṣṭhira directly, it declared, “Your charity and treatment of guests have failed to achieve even a quarter of what a poor brāhmaṇa of Kurukṣetra did to his guest.” As everyone in the court was astounded at the mongoose’s outrageous audacity of disparaging the grand yajña performed by King Yudhiṣṭhira, it recounted the story of a poor brāhmaṇa who acted a magnanimous host. Even today this story epitomises the grandness of the principle of serving the guest with one’s best efforts in Indian civilisation.

The mongoose told that once an impoverished brāhmaṇa used to live in Kurukṣetra along with his wife, son and daughter-in-law. Everyone in the family had to pull their weight in order to make both ends meet. Even at usual times they scarcely had one square meal a day, and then their country was stricken by an accursed famine, driving them even deeper into the mud. One day the brāhmaṇa somehow managed to acquire a handful of barley, which the family crushed and divided into four parts for each of the members. It was when all four had settled down to have the meagre meal of crushed barley for lunch that suddenly another brāhmaṇa appeared at their doorstep as guest. The host brāhmaṇa welcomed him into his home and offered him his own share of the barley. But the little barley proved to be nothing before the guest’s appetite, so when he finished it, the host’s wife gave her share of the barley away to him. When this also failed to appease the guest’s hunger, the brāhmaṇa‘s son and daughter-in-law also in turn gave away their food to the guest. Now, after eating every morsel of the food of the four the guest was happy and content. The guest was none other than Dharmarāja (Dharmaraja; the god of dharma or righteousness, principles and ethics), who was overwhelmed at the brāhmaṇa‘s selfless observation of the principle of serving the guest with the best hospitality. He blessed the brāhmaṇa the he, along with his family, would attain heaven alive.

Finishing the story, the mongoose said, “After the brāhmaṇa departed for heaven with his family, I happened to roll myself over and over again on the little dust of the crushed barley left on the floor of their hut. That is what turned half of my body into gold. Since then I have visited hermitages of innumerable sages and yajña performed by numerous kings famous for their hospitality, but the other half of my body remained as ordinary as it was. I had come to this yajña of Yudhiṣṭhira with the high hope that this time I shall have my chance, but here also the other part of my body did not turn golden. That is what leads me to conclude that King Yudhiṣṭhira’s charity and generosity as a host is no match for the magnanimity of the same of the brāhmaṇa I spoke about.”

In this story the element of half of the mongoose’s body turning golden seems fanciful. However, the brightness of gold, the metal symbolising not only great value but also majesty, certainly becomes an apt metaphor for conveying the great significance of offering selfless hospitality towards the guest, which is the essence of the mongoose’s story.