For me the answer comes from Acts 2 & 4, Hebrews 10, 1 Thessalonians 5, Philippians 2, Colossians 3, and through a multitude of other verses.
So, in my mind, this isn't necessarily people who all live in one subdivision or even one city, but they are a community of believers who ensure there is not need among them. They eagerly spend time together, seeking the Lord. They are kind with one another, understanding, helpful, seeking the fellowship of one another, seeking time to study and learn more about our Lord and His greatness together, worshiping as one, glorifying Him in all we do. If a brother or sister in Christ is in need, they reach out to help them. Their desire should be to be around one another, as there is no one in the world they have more in common with than other believers. Disputes should be able to be handled within the church, not relying on outside worldly counsel or judges. Those who don't know Christ should be envious, even if of nothing else, of the sense of community and love shared among the believers. Christ's love should be so ever present it is oozing everywhere.
Acts 2:44 And all those who had believed were together and had all things in common; 45 and they began selling their property and possessions and were sharing them with all, as anyone might have need. 46 Day by day continuing with one mind in the temple, and breaking bread from house to house, they were taking their meals together with gladness and sincerity of heart, 47a praising God and having favor with all the people.
Acts 4:32 And the congregation of those who believed were of one heart and soul; and not one of them claimed that anything belonging to him was his own, but all things were common property to them. 33 And with great power the apostles were giving testimony to the resurrection of the Lord Jesus, and abundant grace was upon them all. 34 For there was not a needy person among them, for all who were owners of land or houses would sell them and bring the proceeds of the sales 35 and lay them at the apostles' feet, and they would be distributed to each as any had need.
Hebrews 10:23 Let us hold fast the confession of our hope without wavering, for He who promised is faithful; 24 and let us consider how to stimulate one another to love and good deeds, 25 not forsaking our own assembling together, as is the habit of some, but encouraging one another; and all the more as you see the day drawing near.
1 Thessalonians 5:13b Live in peace with one another. 14 We urge you, brethren, admonish the unruly, encourage the fainthearted, help the weak, be patient with everyone. 15 See that no one repays another with evil for evil, but always seek after that which is good for one another and for all people. 16 Rejoice always; 17 pray without ceasing; 18 in everything give thanks; for this is God's will for you in Christ Jesus. 19Do not quench the Spirit; 20do not despise prophetic utterances. 21But examine everything carefully; hold fast to that which is good; 22 abstain from every form of evil.
Philippians 2:3 Do nothing from selfishness or empty conceit, but with humility of mind regard one another as more important than yourselves; 4 do not merely look out for your own personal interests, but also for the interests of others.
Colossians 3:12 So, as those who have been chosen of God, holy and beloved, put on a heart of compassion, kindness, humility, gentleness and patience; 13 bearing with one another, and forgiving each other, whoever has a complaint against anyone; just as the Lord forgave you, so also should you. 14 Beyond all these things put on love, which is the perfect bond of unity. 15 Let the peace of Christ rule in your hearts, to which indeed you were called in one body; and be thankful. 16 Let the word of Christ richly dwell within you, with all wisdom teaching and admonishing one another with psalms and hymns and spiritual songs, singing with thankfulness in your hearts to God. 17 Whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks through Him to God the Father.