Hajj is performed once in a year. Muslims from around the world arrive at Makkah. There are spots around Makkah which are known as places for performing Hajj. Differences are a part of nature. When people from so many places get together, differences will naturally arise. It is impossible to not have differences. Black and white, rich and poor, ruler and ruled, from various countries assemble for Hajj. When different people come together, people with different languages and different cultures, surely there will be quarreling and fighting. But the Quran says that if you fight, your performance of Hajj will be rendered invalid. (2.197) To prevent their Hajj from being invalid, people at Hajj do their best to stay away from fighting. This is training for unity in diversity. That is, being united in spite of differences. To be united in spite of disunity. This is indeed a great principle. Stay united, even if there is disunity. If you face sad experience from someone, you have to forget it all. This means to remain united in spite of differences. Hajj is training to stay united in spite of differences. You cannot be trained for this at home, because you live alongside your siblings and relatives. Then how to be trained for this? When people get together for Hajj from around the world, every person present there is Mr. Different. There you get trained to live together in spite of all the differences, in spite of having different tastes, belonging to different cultures, coming from different generations and countries, having different skin colour, you have to live in harmony with the others. Staying united in spite of all the differences. This is the training one receives at Hajj. This is the greatest formula for unity. This is the greatest lesson of unity imparted to us.