Unnecessary difficulty has been made in the explanation of this phrase. Love displays itself in knowledge and discernment. In proportion as it abounds it sharpens the moral perceptions for the discernment of what is best. The passage is on the line of 1Co 12:31, “Covet earnestly the best gifts,” and the “more excellent way” to attain these gifts is love (1Co 13:1-13). See on Rom 2:18, where the same phrase occurs, but with a different meaning. Some explain things which are morally different.
Sincere (εἱλικρινεῖς)
See on pure, 2Pe 3:1.
Without offense (ἀπρόσκοποι)
See on Act 24:16. It may be explained, not stumbling, or not causing others to stumble, as 1Co 10:32. Both senses may be included. If either is to be preferred it is the former, since the whole passage contemplates their inward state rather than their relations to men.