If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother. Matthew 18:15 (ESV)
Our boundaries must be visible and communicated to others in relationship. Secret boundaries harm relationships.
Our first tendency upon setting a boundary is to keep it a secret, in case other people might judge us. But it is difficult for others to respect our boundaries if they don’t know what they are. By clearly communicating our boundaries to others, our relationship can either grow or become a relationship limited to specific situations. In either case, you are able to maintain your boundaries because all parties understand what they are.