The Catechism in Questions & Answers

290. How is the love for one’s neighbour to be revealed in the congregation?

That which Jesus taught His Apostles also applies to the congregation: “A new commandment I give to you, that you love one another as I have loved you [...] By this all will know that you are My disciples, if you have love for one another” (John 13: 34-35). This instruction to His disciples thus even transcends the “golden rule”.
The commandment to love one’s neighbour, to support one’s fellow human being and help in situations of need, should be especially evident in the congregation: “Let us do good to all, especially to those who are of the household of faith” (Galatians 6: 10). All who belong to the congregation have a duty to treat one another with sincere compassion, kindness, humility, gentleness, and patience.