Do you know of a Buddhist text explaining why living in a community?

Living according to the Dhamma, abiding by the appropriate conduct and having learned the Master's word, are able to expound it, preach it, proclaim it, establish it, reveal it, explain it in detail and make it clear; until, when adverse opinions arise, they shall be able to refute them thoroughly and well, and to preach this convincing and liberating Dhamma.'

DN 16

The phrase "the whole of the spiritual life" characterizes the importance of the Sangha.

SN3.18:4.3: Good friends, companions, and associates are the whole of the spiritual life.

So a contemporary search for non-sutta references might prove fruitful. See the whole of the spiritual life

Namo Buddhaya.I assume you mean Sangha by community. One should live in a Sangha for the welfare and good will of the humans and devas. Sangha i.e. community ,exists out of compassion for the people. I am quoting a sutta which tells why there should be unity in Sangha? This can be very well answer your question why to live in the Sangha?

This was said by the Lord…

“There is one thing, bhikkhus, which, when it appears in the world, appears for the welfare of many people, for the happiness of many people, for the good, welfare, and happiness of devas and humans. What is that one thing? It is unity in the Sangha. When the Sangha is united there are no mutual quarrels, mutual recriminations, mutual denigrations, and mutual expulsions. In this situation those who are unsympathetic are converted and those who are sympathetic increase in faith.”

Pleasant is unity in the Sangha. One who helps those in unity, Who delights in unity and is righteous, Is not deprived of security from bondage. By making the Sangha united He rejoices in heaven for an aeon.

There is some overlap here with ChrisW's answer. The point I would like to emphasize is that for both monks and lay persons, there are benefits of admirable friendship.

Admirable friendship is important for both monks and lay persons, so that they may be positively influenced by the wholesome and skillful qualities of their admirable companions.

With admirable friendship, a lay person could progress on the right path according to AN 8.54:

[The Blessed One said:] "There are these four qualities, TigerPaw, that lead to a lay person's happiness and well-being in this life. Which four? Being consummate in initiative, being consummate in vigilance, admirable friendship, and maintaining one's livelihood in tune.

"And what is meant by admirable friendship? There is the case where a lay person, in whatever town or village he may dwell, spends time with householders or householders' sons, young or old, who are advanced in virtue. He talks with them, engages them in discussions. He emulates consummate conviction in those who are consummate in conviction, consummate virtue in those who are consummate in virtue, consummate generosity in those who are consummate in generosity, and consummate discernment in those who are consummate in discernment. This is called admirable friendship.

Meanwhile, SN 45.2 speaks of the importance of admirable friendship for a monk:

"And how does a monk who has admirable people as friends, companions, & comrades, develop & pursue the noble eightfold path? There is the case where a monk develops right view dependent on seclusion, dependent on dispassion, dependent on cessation, resulting in relinquishment. He develops right resolve... right speech... right action... right livelihood... right effort... right mindfulness... right concentration dependent on seclusion, dependent on dispassion, dependent on cessation, resulting in relinquishment. This is how a monk who has admirable people as friends, companions, & colleagues, develops & pursues the noble eightfold path.

Sutta Nipata 1.3 below states that it's better to wander alone as a monk, if one does not have admirable companions. Of course, having admirable companions is the best option.

If you gain a mature companion,
a fellow traveler,
right-living & wise,
overcoming all dangers go with him,
gratified, mindful.

If you don't gain a mature companion,
a fellow traveler,
right-living & wise,
wander alone
like a king renouncing his kingdom,
like the elephant in the Matanga wilds,
his herd.

We praise companionship — yes!
Those on a par, or better,
should be chosen as friends.
If they're not to be found,
living faultlessly,
wander alone like a rhinoceros.

the question is why to live in community. a little effort to answer has arisen out by a slight thought giving and personal experience. we are very unfortunate not having buddha among us . if he would have been then without asking whether it is need to live in community or not , we would have gone with him .thanks to his magnetism and charisma. then how we would go to live in community?. buddha has said that his teachings will be the guide/lighthouse in place of him after his mahaparinirvana. so we have now option of understanding/studying/practicing his teachings. even though we are kicked by life so many times we dont understand its futility. we think everything as permanent . . with this understanding if we go to any commune, we will play there also with all our weapons i.e greed,anger,hatred etc. so as per my experience it is worthy to be in community membered by like minded members only after having experiential understanding of anitya /impermanence by practising the teaching of buddha . otherwise the community becomes a sort of resort with some sort of resort having some sorts of disciplines of getting up from bed, eating timings etc etc.

Monks, these six are conditions that are conducive to amiability, that engender feelings of endearment, engender feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity. Which six?

"There is the case where a monk is set on bodily acts of good will with regard to his fellows in the holy life, to their faces & behind their backs. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"Furthermore, the monk is set on verbal acts of good will with regard to his fellows in the holy life, to their faces & behind their backs. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"Furthermore, the monk is set on mental acts of good will with regard to his fellows in the holy life, to their faces & behind their backs. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"Furthermore, whatever righteous gains the monk may obtain in a righteous way — even if only the alms in his bowl — he does not consume them alone. He consumes them after sharing them in common with his virtuous fellows in the holy life. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"Furthermore — with reference to the virtues that are untorn, unbroken, unspotted, unsplattered, liberating, praised by the wise, untarnished, leading to concentration — the monk dwells with his virtue in tune with that of his fellows in the holy life, to their faces & behind their backs. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"Furthermore — with reference to views that are noble, leading outward, that lead those who act in accordance with them to the right ending of suffering & stress — the monk dwells with his views in tune with those of his fellows in the holy life, to their faces & behind their backs. This is a condition that is conducive to amiability, that engenders feelings of endearment, engenders feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity.

"These are the six conditions that are conducive to amiability, that engender feelings of endearment, engender feelings of respect, leading to a sense of fellowship, a lack of disputes, harmony, & a state of unity."

AN 6.12

“Well then, monks, I will lay down a training rule for the following ten reasons: 5.11.32

1. for the well-being of the Sangha,
2. for the comfort of the Sangha,
3. for the restraint of bad people,
4. for the ease of good monks,
5. for the restraint of corruptions relating to the present life,
6. for the restraint of corruptions relating to future lives,
7. to give rise to confidence in those without it,
8. to increase the confidence of those who have it,
9. for the longevity of the true Teaching,
10. and for supporting the training.

See reference in this link.

According to the first chapter of Vinaya and it's commentary, Vinaya is for 5000 years of the Buddhist teaching.

People who keep Vinaya is Sangha in the 1st and the 2nd who included people in the 3rd and 4th, they are living like the 5th and the 6th and teach or listen Dhamma with the 7th and 8th minds.

So, the 9th and the 10th of the Buddhism is depending on the strength of communities' supports. If they still keep their unity in training follow the Buddha, they and the previous communities still be able to get the advantage from the Buddha's teaching.

And you shoud see Bhikkhu-aparihaniya Sutta as well...

I have heard that on one occasion the Blessed One was staying in Rajagaha, on Vulture Peak Mountain. There he addressed the monks: "Monks, I will teach you the seven conditions that lead to no decline. Listen & pay close attention. I will speak."

"Yes, lord," the monks responded.

The Blessed One said: "And which seven are the conditions that lead to no decline?

1 "As long as the monks meet often, meet a great deal, their growth can be expected, not their decline.

2 "As long as the monks meet in harmony, adjourn from their meetings in harmony, and conduct Sangha business in harmony, their growth can be expected, not their decline.

3 "As long as the monks neither decree what has been undecreed nor repeal what has been decreed, but practice undertaking the training rules as they have been decreed, their growth can be expected, not their decline.

[4] "As long as the monks honor, respect, venerate, and do homage to the elder monks — those with seniority who have long been ordained, the fathers of the Sangha, leaders of the Sangha — regarding them as worth listening to, their growth can be expected, not their decline.

[5] "As long as the monks do not submit to the power of any arisen craving that leads to further becoming, their growth can be expected, not their decline.

[6] "As long as the monks see their own benefit in wilderness dwellings, their growth can be expected, not their decline.

[7] "As long as the monks each keep firmly in mind: 'If there are any well-behaved fellow followers of the chaste life who have yet to come, may they come; and may the well-behaved fellow-followers of the chaste life who have come live in comfort,' their growth can be expected, not their decline.

"As long as the monks remain steadfast in these seven conditions, and as long as these seven conditions endure among the monks, the monks' growth can be expected, not their decline."