St. Basil the Great writes explaining why one cannot be a Christian alone, but rather why being a Christian means living life in community.
“As the foot has its own ability but lacks others, so that, without the assistance of the other members, it does not find in itself the power to subsist nor help to procure what is lacking to it, so, in the solitary life, what we have is without usefulness and we are without aid in what is lacking to us: for God, our creator, has decided that we should have need of one another, so that, as it is written, we should be united with one another. After this, in the same rule, he adds more:
See! The Lord, in the excess of His condescension, was not content to teach us His doctrine, but in order to give us a clear, an obvious example of His humility, in the perfection of His love, He washed and dried with a towel the feet of His disciples…
But whose feet will you wash? Whom will you care for? How will you put yourself in the last place, if you live alone with yourself? And this other word that it is pleasing and good for brothers to live together, how can this be verified in solitude? A community of brothers is, then, a stadium in which athletes are exercised, a good road towards progress, a continual training, a constant concern for the commandments of God: its end is the glory of God according to the commandment of our Lord, but it also preserves the example of the saints of who the Acts of the Apostles tell us: ‘All the believers were gathered together and they had all their possessions in common’, or again, ‘The multitude of the faithful had but one heart and one soul: there was no one who kept for himself anything that he possessed, but everything was in common.’” (Louis Boyer, The Spirituality of the New Testament & The Fathers, p 337)