John was an elderly man and their leader. He used this expression to show his love for them. See how you translated this in [1 John 2:1](../02/01.md). Alternate translation: "my dear children in Christ" or "you who are as dear to me as my own children" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Two possible meanings are 1) this refers to Satan. Alternate translation: "Satan, who is in the world" or "Satan, who works through those who do not obey God" or 2) this refers to worldly teachers. Alternate translation: "worldly teachers" (See: [[rc://en/ta/man/translate/figs-metonymy]])