Family love extended into the Christian community takes linguistic form in this adjective. Classical Greek applied it to blood relatives and even used it as an honorary title for Ptolemaic rulers. In 1 Peter 3:8, it describes the quality believers should embody toward fellow Christians—the church as a family bound by more than blood. The multilingual evidence (Spanish 'fraternales,' German 'brüderlich') consistently emphasizes sibling affection, while the compound structure (φίλος + ἀδελφός) makes explicit that this love mirrors biological family bonds transposed into spiritual kinship.