The one who says he is in the Light and yet hates his brother is in the darkness until now. The one who loves his brother abides in the Light and there is no cause for stumbling in him.
In John 13:35 Jesus enjoined his followers to live this out by saying, “Your love for one another will prove to the world that you are my disciples.” People fall into two classes, those who are in fellowship with God, and therefore walk in light and love, and those who are not in fellowship with God, and therefore walk in darkness and hatred. A disobedient life shows there is neither religion nor honesty in the person, no matter what faith they claim.
Christian love teaches us to value our brother's soul and to dread everything hurtful to his purity and peace. Love does no wrong to a neighbor; therefore love is the fulfillment of the law (Romans 13:10). The world translated “stumbling” (σκανδαλον) could also be translated as “stumbling block.” As we walk in the light we see the stumbling blocks in our path and can avoid falling into the snares of Satan. We will not easily take offense at what is said or done to us, for love is patient, kind and not jealous (1 Cor. 13:4).
How often do those in the world look at Christians and see infighting, church splits, and other signs of “hating” our brothers? Why would they want to be a part of such darkness? But what a witness it is when they see the light of Christ within us – bearing each other’s burdens, forgiving transgressions, and doing good in the world. How much better our lives and relationships will be as we learn to live in this truth!