Hebrews 13:1 provides, “Let brotherly love continue.” Now, the culture may broadly state that brotherly love is a good thing. Yet, we must recognize that such an idea (to the extent that it actually exists), derives from Christianity. This point can be seen in the comment by William Lane, from his commentary on Hebrews:

It is important to appreciate that this was something new. In the second half of the second century the satirist Lucian of Samosata explained to a correspondent, Cronius, that the relationship among Christians is unusual; they are to regard one another as “brothers.” He illustrates his point by calling attention to the Christian attitude toward material possessions and grounds in the teaching of Jesus their willingness to share what they own with one another:

Moreover, their original lawgiver persuaded them that they should be like brothers to one another.. … Therefore, they despise all things equally, and view them as common property, accepting such teachings by tradition and without any precise belief (Peregrinus 13).

Lucian’s remarks indicate that an educated person in the second century was quite unprepared for the Christian notion of φιλαδελφία expressed in the admonition, “Keep on loving each other as brothers.” The expansion of the term to include men and women beyond the immediate family was considered ludicrous. Ironically, Lucian’s choice of the Christian attitude toward personal property to illustrate Jesus’ teaching is insightful. It is precisely a willingness to share possessions unselfishly that is characteristic of the relationship among members of the same family. New perspectives concerning familial relationships will inevitably have implications for attitudes toward personal wealth (cf. 13:5) (see Lane, PRS 9 [1982] 270).

Hebrews, 510.