"Anyone who says" or "Those who claim" (UDB). This does not refer to a specific person.
## he is in the light ##
This is a way of speaking about living right. When people do what is right, they can do it in the light, and not hide in the dark. This can be translated "he does what is is right" or "he is in the light doing what is right." (See: [[rc://en/ta/man/translate/figs-metaphor]])
## is in the darkness ##
This is a way of speaking about living sinfully. When people do what is wrong, they like to hide in the dark. This can be translated as "is in the darkness, doing what is evil."
## there is no occasion for stumbling in him ##
"nothing will cause him to stumble." The word "stumbling" is a metaphor that means to fail spiritually or morally. This could be translated as "nothing will cause him to sin" or "he will never fail to do what is pleasing to God."
## is in the darkness and walks in the darkness ##
This same idea is said twice to bring attention to how evil it is to hate a fellow believer. AT: "is living in darkness" or "is living in the darkness of sin" (See: [[rc://en/ta/man/translate/figs-parallelism]])