In chapter 13 there are a number of what the NIV calls 'concluding exhortations'. Some of these have immediate relevance to the situation of the Hebrew Christians, others seem to bear little relation to the dominant theme of the letter, yet obedience to each of them will certainly strengthen and encourage believers to remain faithful to the Lord.
This command is not unique to this letter, but in the context of this letter has the significance that loving our fellow Christians will encourage them in the midst of their hardships and sufferings. It is a common human trait to turn away from suffering, to avoid those who are going through trouble, yet that is the time when observable and tangible love is most needed. In addition, when we ourselves are experiencing suffering it is quite common that we become preoccupied with our own hardships and problems to the extent that we fail to see the needs other people have for our love.
So this command to 'keep on loving each other' cuts both ways, and is acutely relevant to the main purpose of this letter.
This command to hospitality, while reflecting commands in other parts of Scripture, also has special relevance to the context of the letter, where hardship and persecution render hospitality not just a nice, kind thing to do, but, sometimes, an urgent necessity.
In addition, hospitality was highly commended in both the Jewish and Greek heritage; it was therefore, quite apart from any other Biblical commands, a practice which would contribute to the good standing of Christians in the community. Failure to practice hospitality would expose them to further criticism.
The reason for entertaining strangers given in 13:2 is that 'by so doing some people have entertained angels without knowing it'. This is most likely a reference to Abraham (Genesis 18), Lot (Genesis 19) and perhaps Gideon (Judges 6). The text does not say that we can expect some of our visitors to be angels in disguise. What we can say is that when we 'entertain strangers' we have no idea how God is going to use them as his messengers to impact our lives in some way. (The word translated 'angels' means 'messengers' or 'sent ones'.)
In a situation in which Christians were being persecuted by the Roman government and suffering imprisonment and mistreatment at their hands, these are particularly relevant commands. The added 'as if you were their fellow prisoners' and 'as if you yourselves were suffering' give them added power. The writer has already reminded his readers of how they had done just this previously (10:32-39), even though doing so had jeopardized their own safety. This is the kind of love that is willing to expose itself to danger for the sake of the other, for association with those being persecuted has the potential to bring one under the same attack.
We find this command here along with the other commands to love, and indeed it is a command to love - not only one's marriage partner, but to so love the other believers with brotherly love that one would not even dream of betraying them by entering a sexual relationship with their marriage partner, and to so love other believers that one would never dream of entering a sexual relationship with them outside of marriage.
The point is made that God's judgement will fall on the adulterer and sexually immoral. Check out Ephesians 5:6 and Colossians 3:5-6.
Just as sexual lust is incompatible with Christian love, so is money-lust incompatible with Christian love. The writer gives us several pointers to avoid a sinful love of money:
In a situation of persecution earthly wealth and possessions are often lost. In striving to avoid this forfeiture of possessions there is the two-fold danger of abandoning faith in God and abandoning or disassociating oneself from other believers. The extreme circumstances call for a love of God and of the Christian neighbour that transcends the love of money, and is willing to be content and to trust in the promises of God.
They kept on believing: you do the same.
That same Jesus who sustained the leaders in their faith yesterday is the same Jesus who will sustain the Hebrews in their faith today and forever. He doesn't change. He is the eternal one, the first and the last, the one who ever lives [Psalm 102:27; Revelation 1:8,17,18]. What they heard was true of him yesterday is also true today. That same perfection he had yesterday is his today. That perfect salvation he granted yesterday is equally perfect today. It needed no human additions yesterday; it needs no human additions today.
Because their leaders who spoke God's word to them persisted in faith, because Jesus is the perfect, ever constant, dependable, unchanging One, they ought not to be carried off by strange teachings, because:
FF Bruce comments: "Jesus was led outside Jerusalem to be crucified, and this is regarded as a token of His rejection by all that Jerusalem represented. To have His messianic claims rejected by the leaders of the people was ... a stigma; to be cast out and crucified added to that stigma. ... in the person of Jesus, God had again been rejected in the camp; His presence was therefore to be enjoyed outside the camp, where Jesus was, and everyone who sought Him must go out and approach him through Jesus. In this context the 'camp' stands for the established fellowship and ordinances of Judaism. To abandon them, with all their sacred associations inherited from remote antiquity, was a hard thing, but it was a necessary thing. They had been accustomed to think of the 'camp' and all that was inside it as sacred, while everything outside it was profane and unclean. ... in Jesus the old values had been reversed. ... To be associated with (Jesus) meant bearing the stigma that He bore; it meant taking up the cross and following Him; it meant leaving the shelter of a religio licita for a fellowship which invited the hostile attention of imperial law; but if, like Moses, they 'looked unto the recompense of reward', they would see that the stigma carried eternal glory with it. There, 'without the camp', stood Jesus, calling them to follow Him. Inside they felt secure; they knew where they were amid its familiar installations; they were psychologically insulated from the world outside. But Jesus claimed the world outside for Himself." (The Epistle to the Hebrews, pp 402-404).
These Hebrew Christians were being pressured to return to the Old Testament sacrificial system as a means of obtaining forgiveness and an expression of worship to God. In these two verses they are told:
This is the final command. Having told them of the extreme superiority of Jesus Christ and his once-for-all-sacrifice, having exhorted them not to fall short of salvation because of unbelief, having given them historical examples of true faith that endured, having commanded them to keep their eyes fixed on Jesus, having encouraged them to understand their current hardship as their heavenly Father's loving discipline, having provided them with various practical directions for expressing and cultivating their faith, the writer now gives them this one last command, which is, like all of the others, geared to protect them against the overt and subtle suggestions of the false teaching that was threatening to lead them away from Christ. He says:
God has appointed leaders in his church; it is their responsibility to feed his sheep - to teach the truth to those who belong to Christ. The responsibility of those who are the 'sheep' is to obey and learn from those whom God has put in charge. To go after false teaching, to depart from Christ, discarding the pure message of truth taught by the appointed leaders of the church, is to be disobedient to God's authority structure.
[We are faced here with the terrible possibility, which is sadly often an actual reality, that those who are in leadership may themselves become deceived and pursue false teaching, departing themselves from the true truth with which they are supposed to be feeding the flock of Christ.]
This final prayer affirms the superiority of Christ and his sacrifice:
In addition, this prayer acknowledges that the perseverance of believers is in God's hands:
Having said all that needed to be said by way of encouraging these believers, and us, to actively persevere in faith in Christ, he now commits us to God, in whose hands he knows we are secure.