True Christian fellowship must be based on light. We can walk in true and deep fellowship with one another only if we are willing to walk in the light. This involves a willingness to be ourselves with each other - avoiding all sham and hypocrisy. This is how God intends Christians to walk with one another. Remember, the first sin publicly judged by God in the early Church was hypocrisy (see the story of Ananias and Sapphira recorded in Acts 5:1-14).
Sin has caused all of us to wear masks in our mutual relationships. We are afraid and ashamed of being known as we actually are. We live in a world full of people wearing masks; and when people get converted, they don't take off their masks. They wear their masks and go to meetings and meet with other people - and call that fellowship. But such fellowship is a farce. Yet the Devil has got most Christians satisfied with just that.
It is true that it is impossible for any of us to remove our masks completely. Living in a sinful world and fellowshipping in an imperfect church, and bound by the flesh ourselves, it is neither possible nor desirable to be completely honest with others. Total honesty is not feasible, because we can't see ourselves fully. Neither is it advisable, because it may hinder others.
We certainly need wisdom in being honest. But we should never pretend to be something that we are not. That is hypocrisy - and hypocrisy was condemned outright by Jesus.
A self-righteous, Pharisaical attitude is what prevents many Christians from being channels of help and encouragement to others. Our attitude must be such that our fellow-believers and others will feel free to come to us and "let their hair down" and unburden themselves, knowing that they will meet with sympathy and understanding, and that they won't be despised for their ignorance or for their failures.
The world is full of lonely, tense, fear-ridden and neurotic people. Christ has the answer to their problems, but that answer should come to them through His Body, the Church. But alas, most Christians are so self-righteous and unreal that they drive away people in need.
Keith Miller says in The Taste of New Wine,
"Our modern church is filled with many people who look pure, sound pure, and are inwardly sick of themselves, their weaknesses, their frustration and the lack of reality around them in the church. Our non-Christian friends either feel, 'That bunch of nice untroubled people would never understand my problems'; or the more perceptive pagans, who know us socially or professionally, feel that we Christians are either grossly protected and ignorant about the human situation, or are out-and-out hypocrites."
We need to learn what it is to have honest fellowship with others on a personal level - and we can all begin with one person.