JMNT(i)
20 If anyone may up and say, "I am constantly loving God, " and yet may be habitually hating (or: would keep on regarding with ill-will) his brother, he is a liar (he exists being a false one). For the one not habitually loving his brother (= member of the community, or, fellow human) – whom he has looked at and now sees – he continues being unable and has no power to be loving God, Whom he has not seen (or: looked at).