Hajj is the means to reach the unity of the Muslims

And proclaim to the people the hajj [pilgrimage]; they will come to you on foot and on every lean camel; they will come from every distant pass –

That they may witness [i.e., attend] benefits for themselves and mention the name of Allah on known [i.e., specific] days over what He has provided for them of [sacrificial] animals. So eat of them and feed the miserable and poor.