The biggest example that spirituality unites was set by Lord Krishna himself and followed him Mahavira (24th Tirthankara of Jainism, preceptor), Gautama Buddha further followed by Jesus Christ and Prophet Mohammed.
In times of all these enlightened ones irrespective of what religion a seeker followed, masses followed teachings of these enlightened ones. Spirituality is something that relates to our inner self, the very core of life. Spirituality is the sap of religion. We exist because spirituality exists.
The word spirituality stems from the root word spirit which existed inside all living beings including human form as our soul atman, the consciousness. None in this world can negate presence of spirit within. It is this spirit that manifested human form to cleanse self of dross impurities within.
Path of spirituality means inner journey taken by seekers to reach the spirit within. Only after reaching their true inner self existing in their heart, they realized that they were in fact the spirit existing in the heart and it was the human body that was manifest by it.
We truly are a spiritual traveler on a cosmic journey.
To sum up, spirituality is the underlying spirit existing within all living beings. At spiritual level all bonded together behind one single universal entity we called God Almighty.
Materialism relates to well-being of the physical manifest body. Materialism has nothing to do with spirituality. Dominated by a bloated ego most human beings on mother earth pursued a materialistic goal in life. This led to frequent altercations amongst human beings, the cause for all distress, depression and anxiety world over.
It is primarily materialism that divided human beings, even lower forms of life. All discords disharmony originated from material disputes never spiritual. On a religious or spiritual level one may possess a very distinctive point of view but the fight was limited to mostly verbal arguments. On the material level, the fight sometimes escalated to physical harm.
Materialistically two human beings after the same goal could never come to a truce while spirituality the goal of all human beings is one, reaching god.