John 15:12

12.This is my commandment. Since it is proper that we regulate our life according to the commandment of Christ, it is necessary, first of all, that we should understand what it is that he wills or commands He now therefore repeats what he had formerly said, that it is his will, above all things, that believers should cherish mutual love among themselves. True, the love and reverence for God comes first in order, but as the true proof of it is love toward our neighbors, he dwells chiefly on this point. Besides, as he formerly held himself out for a pattern in maintaining the general doctrine, so he now holds himself out for a pattern in a particular instance; for he loved all his people, that they may love each other. Of the reason why he lays down no express rule, in this passage, about loving unbelievers, we have spoken under the former chapter.