R. Yitzchak took the lesson about serving others and elevated it to cosmic proportions. If we want to find someone greater than both R. Gamliel and Abraham in the act of serving, he said, we need only look at the Shechinah — God's own Presence.
The Shechinah, R. Yitzchak explained, supplies food to every creature that enters the world. Not occasionally, not as a special favor, but at all times. And not merely to the righteous, but to everyone — in accordance with their individual needs. God feeds each living thing according to what it requires, and He satisfies all living things with good will.
Then R. Yitzchak made the truly radical point. God does not only feed worthy people and tzaddik (a righteous person)im (the righteous). He feeds evildoers. He feeds idolaters. People who deny Him, who worship carved images, who violate His commandments — they still eat, they still drink, they still receive sustenance from His hand every single day. The Shechinah withholds nourishment from no one.
The practical conclusion followed with devastating logic. If the Shechinah — God Himself — serves food to idolaters and sinners without complaint, how much more so should R. Gamliel pay personal attendance upon Torah sages and scholars? If God serves the unworthy, surely a human leader can serve the worthy. The standard of hospitality is not set by human custom. It is set by the Creator of the universe, who feeds everyone, always, without exception.