So if there is any encouragement in Christ, any comfort from love, and participation in the Spirit, any affection and sympathy, complete my joy by being of the same mind, having the same love, being in full accord and of one mind.
If we are Christians then it should affect our relationships. Communities of Christians should be marked by the relationships between people. If we are participating with the Spirit, working with the Spirit, being led and guided by the Spirit, then we should be "in full accord" with each other, working alongside each other with one mind, the same aim, the same goal. If we know we are loved by God even though we don't deserve it, we start to show love to others even though they may not deserve it. When we realise the message of the gospel, then it changes everything about our attitude and motivation, and we are "of the same mind" with other believers, other people who have recognised the same thing.
Unity should be the mark of people trusting in Jesus but that doesn't mean that we should pursue unity as if it is the ultimate goal in itself. We are united around Jesus. Unity should be motivated by God's love for us and it is only possible because of those things. Man made pursuit of unity is always fragile because it is built around us. Gospel centered unity is the only type of unity that can last.
We need to examine our relationships and evaluate what they reveal. Do they reveal that we have understood the gospel? Do we love each other? Then have we really understood what it means that God loves us? Are we of the same mind, the same vision? Then are we really living in participation with the Holy Spirit, or are we just doing our own thing?