Christianity was a wandering movement that often depended on the hospitality of both Christians and non-Christians. The instruction to “not forget” to show hospitality probably does not simply refer to the failure to think about taking someone in but about willful neglect.
Paul does not have in mind hospitality only for fellow believers. He reminds his readers that by entertaining strangers some have unwittingly entertained angels (Heb. 13:2). He probably had in mind the visit of the three men to Abraham and Sarah (Gen. 18:2–15). Offering hospitality implies sharing possessions with another person and suffering with others, which is what Jesus did for us (Heb. 2:10–18).
Brotherly love toward those in prison implied not simply that believers remembered prisoners in their prayers but that they also provided relief through material and emotional support. There was a risk of willful neglect of prisoners. Those who provided material and emotional support to those condemned by society identified themselves with them. In some sense they became “partners” with them and made themselves vulnerable to social abuse (Heb. 10:32–34).
Paul’s exhortation uses images and language to encourage the readers in regard to prisoners. First, the author evokes the readers’ own support for their incarcerated brethren in the past. They had become “companions” (NKJV) or “partners” to those who had been “publicly exposed to reproach and affliction” (Heb. 10:33, ESV). Second, the language of “mistreatment” echoes the example of Moses, who chose “rather to be mistreated with the people of God than to enjoy the fleeting pleasures of sin” (Heb. 11:25, ESV). Finally, Paul captures the ideal of brotherly love. He reminds the readers that they “also are in the body” (Heb. 13:3, ESV). They share the same human condition and should treat others as they would like to be treated if they were in the same circumstances; that is, in prison. The people should, then, provide material and emotional support to prisoners, showing them that they are not abandoned.
Paul also warns the readers against sexual immorality and greed because they are two grave threats to brotherly love. In fact, New Testament authors and ancient moralists noted a connection between them.
Paul’s call to honor marriage implied the avoidance of anything that would belittle it. This avoidance included abstaining both from violation of the marriage oath and from unbiblical divorces (compare with Matt. 19:9). The exhortation to keep the marriage bed undefiled refers to avoiding the profanation of marriage through sexual relationships outside of marriage. The expression “fornicators” refers in the New Testament to every form of sexual immorality (1 Cor. 5:9–11; 6:9; Eph. 5:5; 1 Tim. 1:9, 10; Rev. 21:8; 22:15). In addition, Greco-Roman society was lax in regard to sexual ethics. A double standard was common; this allowed men license in their sexual relationships as long as they were discreet. Paul warns, however, that God will judge adulterers. Believers should not let social conventions establish their own ethical standards.
“Love of money” was one of the main categories of vices in the Greco-Roman world. In fact, in another letter Paul referred to “love of money” as the source of all evils (1 Tim. 6:10).
The defense against this vice is an attitude that Paul encourages in several epistles. First, they should “be content” with the things they have (also 2 Cor. 9:8; Phil. 4:11, 12). Furthermore, Christians should believe and embrace God’s promise that God would “never leave . . . nor forsake” them (Heb. 13:5). This promise was given at several places and moments to His people and is available to us today (Gen. 28:15; Deut. 31:6, 8; Josh. 1:5; 1 Chron. 28:20). Believers, then, are invited to respond to God’s promise with the words of Psalm 118:6 (ESV): “The LORD is on my side; I will not fear. What can man do to me?” This reference to Psalm 118 is appropriate because the psalmist expressed there his confidence in God, despite the suffering inflicted upon him by unbelievers.