The Lord appeared to Abraham near the great trees of Mamre while he was sitting at the entrance to his tent in the heat of the day. Abraham looked up and saw three men standing nearby. When he saw them, he hurried from the entrance of his tent to meet them and bowed low to the ground.
a 13th century icon by Andrei Rublev called The Old Testament Trinity.
He said, “If I have found favor in your eyes, my lord, do not pass your servant by. Let a little water be brought, and then you may all wash your feet and rest under this tree. Let me get you something to eat, so you can be refreshed and then go on your way—now that you have come to your servant.”
“Very well, they answered, do as you say.” So Abraham hurried into the tent to Sarah. “Quick,” he said, “get three seahs of the finest flour and knead it and bake some bread.” Then he ran to the herd and selected a choice, tender calf and gave it to a servant, who hurried to prepare it. He then brought some curds and milk and the calf that had been prepared, and set these before them. While they ate, he stood near them under a tree.
This is also how we understand the inter-relationality of the Trinity. For Christians, God is the one who welcomes us to the table, welcomes us as strangers to the food and community of the Trinity. Hospitality is at the core of Christian identity and practice. It is one of our primary witnesses to our life together in Christ.
The Other Six Days 