Thoughts behind the act

The following paragraph is an excerpt from an article by Rabbi Mendel Weinbach.

In the end of days our Sages tell us that there is going to be a world trial, like a post Nuremberg trial, except that there is going to be only one judge: The One Judge; G-d. And G-d will ask the 70 Nations: "what did you do to promote Torah in this world?" And the Talmud says that all the Nations will come forward with their new understanding of world history, and they will try to take credit for having enabled Jews to learn Torah by providing them with such necessities as marketplaces, roads, bridges, and bathhouses. But G-d will reject their claim telling them: "Although your achievements did actually benefit the people of the Torah, it was only because My Divine Plan of World History put you in a position to do so; but, in fact, your motivations were purely selfish ones: either for economic exploitation or physical gratification."
http://ohr.edu/1307

This morning I pushed open the door to the elevator in my building and a neighbor, laden with packages, walked in and said "thank you" as I was exiting. "Why did he say thank you to me?" I asked myself. I wasn't opening the door for him. I opened the door to let myself out. And then I recalled Rabbi K. speaking this week about the above related story in the Talmud. If only I had had in mind to help out my neighbor, I would have been credited with a mitzvah. The same act of opening a door can be viewed as a positive deed or can be judged as an act solely for one's own benefit, depending upon the person's thoughts when performing the act.