Mahatma Ghandi famously once replied when asked if he was a Hindu:
“Yes I am. I am also a Christian, a Muslim, a Buddhist and a Jew.”
Here are some more of M. Ghandi’s statements about the inherent unity of religion qua spirituality, from (http://www.mkgandhi.org/religionmk.htm) :
I believe in the fundamental Truth of all great religions of the world. And I believe that if only we could, all of us, read the scriptures of the different Faiths from the stand-point of the followers of those faiths, we should find that they were at the bottom, all one and were all helpful to one another.
Belief in one God is the cornerstone of all religions. But I do not foresee a time when there would be only one religion on earth in practice. In theory, since there is one God, there can be only one religion.
The one religion is beyond all speech. Imperfect men put it into such language as they can command, and their words are interpreted by other men equally imperfect. Hence the necessity for tolerance, which does not mean indifference towards one’s own Faith, but a more intelligent and pure love for it.
Living faith in his God means acceptance of the brotherhood of mankind. It also means equal respect for all religions. It would be height of intolerance…to believe that your religion is superior to other religions and that you would be justified in wanting others to change over to your faith.
All worship the same Spirit but as all forms do not agree with all, all names do not appeal to all. Each chooses the name according to his associations and He being the Indweller, All-powerful and Omniscient, knows our innermost feelings and responds to us according to our hearts.
Faith in any form can bring healings of the Heart and Better Endings to those who believe.