How are we supposed to interpret this prescription? Who should be included in the category "stranger"? How would we show hospitality to someone in our country that we did not invite in?
The letter continues with its instructions: Remember those in prison. And not just remember, empathize. Are we allowed to limit this just to people who are imprisoned for certain beliefs rather than have to think about the other prisoners, those who we think really should be put somewhere out of sight.
Then the message comes home--literally. "You married people, stay faithful."
And, in this time of economic difficulty, what do we do with the command to keep our lives free from love of money?
To summarize, care for strangers, prisoners, spouses, but don't obsess so much about money. After all, God is with us and will help us through it all.
Thomas Long in his commentary on Hebrews, says about verses 15-16:
We do not make, of course, the same sacrifice that Jesus offer; his was "once for all" (10:10). Our sacrifices are praising God, confessing God, name in public, doing works of mercy, and sharing what we have with others--in other words, right out there in public view we are to worship, evangelize, empathetically serve the needy and exercise generosity to others. Such "sacrifices are pleasing to God", which is one of the marks of faith.