Andreas of Caesarea, on 1John 4:21

“And this commandment we have from God, that he, who loveth God, love also his brother.”

“The person who loves God keeps his commandments, and loving one's brother is the fulfillment of those commandments. The person who does not love his brother has not kept the commandments and by not keeping them has not loved God. The one who says he loves but does not do so is a liar.”

Imported from an open dataset — not yet checked against the printed edition.