Akbar was the emperor of India during the time of Guru Amar Das. He was a virtuous ruler who respected holy men and had a love for divine teachings. His grandfather had met with Guru Nanak Dev ji and his father had met with Guru Angad Dev ji. He himself went to go visit Guru Amar Das ji, the third Guru.
When the emperor requested to see the Guru something funny happened. The emperor was used to people giving him all the privileges in the world but the Guru refused to see him until he had eaten langar with the common people. Guru Amar Das had made a rule that anyone who wanted to see him had to eat langar first. So everyone who met the Guru, sat down in the langar lines with all the common people and ate the same food everyone is served. This way everyone knew that we are all equal and God gives to us all. He made no exception even for the great emperor Akbar.
This showed that the Guru respected God's law, that everyone is equal. It showed that we are all human and we are all equally loved in God's eye's. The Guru didn't care if someone was rich and powerful, he didn't accept these kinds of social rules. So the emperor did indeed sit and eat with everyone else. Akbar was impressed with Guru Amar Das and what an honest holy man he was. This story tells us that God provides for everyone. Everything we need will come to us.