Separation naturally brings anxiety - we want to know how the other is doing. Hence Paul was concerned for the Thessalonians. Not having phones or Facebook, he dispatched Timothy to visit and report back. The news was good: v6 talks of faith and love. I.e. they were still in Christ and still proclaiming the Kingdom.
So in v8 Paul is able to say 'now we really live' - his wellbeing depended on theirs. This is Paul's principle of 'the body': despite miles (and years?) of separation they were part of one body, they were connected. That unity stemmed from being in Christ and sharing the same God given purpose. Just as Timothy was a co-worker in God's service of sharing the good news (see v1), so were the Thessalonian Christians. Paul travelled a wide area preaching the Kingdom, and when people came to faith they were discipled and became active in the same Kingdom vision that he so tirelessly worked for.
For us as a church in Ely, we want to see Kingdom life appear across the whole city. Being in Christ and sharing the same God given purpose bring a fundamental sense of unity, surpassing many differences and diversity. This unity will be key as groups potentially start ministering in different parts of the city, causing them to be unable to all meet centrally as much as they do now. Although sometimes elsewhere, we can still be one body, remaining as one church with one organisational structure that serves ministry in all the areas.
Interestingly we already see this model working in Ely Foodbank: it has distribution points and volunteers in other towns, but all share a strong common purpose (to help people in crises need) that enables us to work together within one organisation (one charity, one set of trustees, accounts etc.).
In v12 Paul prays for the Thessalonians that their love would increase and overflow: both for each other and for everyone else. Their outreach and their 'in house' love went hand in hand. Can we be the same? To start with, lets ask ourselves the simple yet profound question:
[IN] Do you love the body?
Challenge: Bless a different part of the body
Make a point of finding someone who you don't know that well, ask them about the ministry areas they are involved with, encourage and pray for them.
See also in v10 Paul wants to visit in person, i.e. the importance of actually meeting together. We know our virtual world (of Facebook etc.) is no substitute for actually turning up! So even though some Sundays people may be out ministering in other places, on the other weeks they should still come together for our corporate worship, whole church prayer and so on.
V10 also talks of supplying what was lacking. We don't exactly know what Paul had in mind, but Paul gives enough hints that since this is a two way relationship he doesn't mean to be superior or dispense some kind of faith pill that only he could give. No, he simply wants to be there and bless them. That is our model of corporate worship: each person can bring something to bless others. As we meet for worship week on week that worship comes in our hands: what we bring from the week, the work we have seen God do through us across the city. This is the body in action, celebrating God and His work as one united body.