Whether--or (εαν τε--εαν τε). "Both if--and if" (condition of third class with present subjunctive (ζωμεν--αποθνησκωμεν). Both living and dying are "to the Lord." Paul repeats the idiom (εαν τε--εαν τε) with the conclusion "we are the Lord's (του κυριου εσμεν). Predicate genitive, "we belong to the Lord."