The truth is spoken of as if it were an object that could be inside the believers. AT: "he does not believe what God says is true" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This can be stated in active form. Possible meanings are 1) "the love of God" refers to a person loving God, and "perfected" represents completely or fully. AT: "it is that person who loves God completely" or 2) "the love of God" refers to God loving people, and "perfected" represents completing its purpose. AT: "God's love has achieved its purpose in that person's life" (See: [[rc://en/ta/man/translate/figs-possession]] and [[rc://en/ta/man/translate/figs-activepassive]])
The phrase "we are in him" means that the believer has fellowship with God. AT: "When we obey what God says, we can be certain that we have fellowship with him" or "By this we know that are joined to God" (See: [[rc://en/ta/man/translate/figs-metaphor]])
To remain in God means to continue to have fellowship with God. AT: "continues to have fellowship with God" or "stays joined to God" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Conducting one's life is spoken of as if it were walking. AT: "must live as he lived" or "should also obey God just as Jesus Christ did" (See: [[rc://en/ta/man/translate/figs-metaphor]])