Paul’s appeal in Phil 2:1 is based on what the church already has. The ESV translates these short phrases as conditions (“if there is any….”) This does not mean Paul is unsure of the state of the church in Philippi. The Greek syntax does not express uncertainty and might be translated as “since there is…” For example, I might say “If it is morning, if coffee is made, then I am going to drink a cup of coffee.” In this case, the sentence is really, “Since it is morning….”
Encouragement in Christ can refer to both comfort and exhortation. The noun (παράκλησις) is something that emboldens you to act (BDAG). The context will make it clear if the word refers to encouraging the timid to act or exhorting someone who needs to be corrected. One side of the word is tenderly comforting a person who is hurting, the other is a swift kick in the pants to motivate a person the right direction!
Comfort from love may refer to consoling for a person who is hurting in some way, it is a “friendly word” (TDNT 5:820) . The noun (παραμύθιον) appears in the LXX only in Wisdom 3:18, referring to people who will have no comforter on the day of Judgment. Encouragement and comfort naturally go together. In 1 Thess 2 Paul uses the concepts of mothers and fathers to describe his ministry with that Church, gentle like a mother, encouraging like a father.
Participation or fellowship in the Spirit may refer to the close association all Christians have because the share in the same Holy Spirit. Since all believers have the same Spirit, they ought to have complete unity.
Affection and sympathy are both deep emotional responses one typically has for someone you genuinely love. Affection (σπλάγχνον) originally referred to the inner parts of a person, their bowels or entrails, where emotions are felt most strongly. Sympathy is also a stronger word than in English, οἰκτιρμός is the deep compassion God has for humans (1 Kings 8:50, Zech 7:9, רַחֲמִים). Taken together, the words refer to genuine, “heartfelt sympathy” for one another.
Does this mean there is no room for dissent? American culture almost requires people to have different ideas and opinions, Paul sounds like a cult leader who will squash any dissent! One criticism Atheists sometimes use is the vast differences between the various denominations of Christianity. Which Christianity is the real one? Compare a traditional Catholic to a radical Protestant and there are very few things that seem the same. There are good reasons for these differences, but the differences should not obscure the similarities. There are non-negotiable beliefs that make one a Christian (God, Scripture, Jesus, Atonement) and others that are simply differences created by culture and history.
Far from demanding conformity in everything, unity in the church functions like it does in a real family. There are similarities and differences, but what ultimately counts is the family! The first believers may have been ostracized by their families when they became Christians. If that is true, the church becomes their adopted family. Paul’s description of the church as a family highlights the similarities yet allows for differences. Some have the view that the church is a kind of factory producing identical clones and squashing thought and dissent. This is not at all Paul’s point here!
Since the church is a family, the members of the family ought to be supportive of one another, characterized by the same sort of grace and forgiveness one experiences in an ideal family. This requires humble service from all members of the community, including the leaders. In fact, the best example of humble service is in fact Jesus himself.