"He looked up and noticed three men standing nearby. When he saw them, he ran to meet them and welcomed them, bowing low to the ground. 'My lord,' he said, 'if it pleases you, stop here for a while. Rest in the shade of this tree while water is brought to wash your feet. And since you've honored your servant with this visit, let me prepare some food to refresh you before you continue on your journey.' 'All right,' they said. 'Do as you have said.'"
Have you ever openly invited someone you didn't know into your home? You didn't know they were coming, you haven't cleaned your bathroom or vacuumed your carpets. You don't have any food prepared and your kids (or animals) are running amuck. But you see people in need and do you open up your home to them? Do you let them into the privateness of your life? Do you feed them the only food you have left in your pantry? Do you consider yourself their servant?
I have no doubt that Abraham's visitors were actually angels and Christ, but Jesus even said "I tell you the truth, when you did it to one of the least of these my brothers and sisters, you were doing it to me!" Matthew 25:40