When we say someone is our brother or sister in Christ we celebrate the fact that through Jesus we are saved. However, we seldom think about the other side of the coin.
The fact that we need saving means that we are sinners and as brothers and sisters in Christ we all have sin. We have our brokenness and we easily fall into sin.
I think the fact that we are sinners and are saved is a calling for us to Love one another. A realization that not one of us is better than the other, to share in the goodness and the redemption that God brings, to share in the good times and the bad times. Is that not Love?
I believe that God makes all things beautiful even our brokenness. In saying that someone is you brother or sister in Christ is not only affirming the good in them, but also acknowledging and understanding our shared fallen nature. In doing this we come to appreciate and Love each other more.
Truly we are all the same, in need of grace, in need of mercy.