Jesus criticized the scribes and Pharisees and their approach to the law of God:
Matthew 23:4 — “They tie up heavy burdens and lay them on men’s shoulders, but they themselves are unwilling to move them with so much as a finger."
In other words, they laid the unbearable demands of obtaining righteousness by works on the people (and thereby only magnified the burden of their sins) but did nothing to help them out with that load (for example by pointing to the Messiah as the One who could deliver them from it if they would trust Him).
Paul tells us it is not to be this way in the church, where we are bound together as a body in the Lord, Jesus Christ. Here, we have all been relieved by Jesus of that crushing load of our sin (just as Pilgrim lost his burden at the cross in Pilgrim's Progress), but now as we become aware of others in burdensome hardship or difficulty in the fellowship, we are to bear that weight with them. This is true fellowship, and this is fulfillment of the law of Christ (to love one another).
It is a rich blessing indeed to belong to a fellowship where brothers and sisters rally around one who is in need and help them out, not prying into their personal matters so they can gossip about them, but expressing practical love and concern in the Name of Christ. We may never know more than a small portion of the instances where this takes place, but we will very easily know if we are in a fellowship like this or not. How? When we are at home alone and members of the church invite us into their own homes, and offer us a place at their meal tables rather than have us be alone. When we mention something that is happening in our lives and receive a heartfelt (and not synthetic) "is there anything I can do to help". Being in church like this, we know we belong, and we know that others will draw near to us when we have need of help. Naturally, we must also have the heart of love that is prepared to offer help to others, to sacrifice our own comforts and interests if necessary so that a brother or sister can be assisted with their hardships and burdens.
All the way through this series, we have been pointing out that true fellowship cannot happen when the church does not gather and the members hardly know each other. It must be self evident in this case. How can I get help with my burden if I never come to church and no-one else knows? How can I help someone with their burden if I never see them to find out what their situation is?
We see enough superficial fellowship in this day and age, and it must be time to rediscover all that is possible in the body of Christ, according to the Word of God!