Rabbi Scott Perlo has an article on HuffPo about the tension. For him, spiritual is the immediate, direct experience of God. Religion, on the other hand
incorporates generations of learning and has grown wise and thoughtful. Religion is patient in a measure that spans lifetimes, and knows the depth of things. Its foundations are hesed -- care and tzedek -- justice. It has plumbed both our mortality and our divinity, and speaks to us of our greatness and our smallness in the same breath. Religion helps us understand life.
Religion ... smothers spontaneity and individuality. It struggles to see people as different from one another (a relatively recent psychological discovery, as an aside). It does not thrill with its quickness, for it is not quick, and prefers rhythm over syncopation, harmony over innovation.
Yes, BUT. "Religion" is a collection of memories/texts/experiences/discourses/traditions/memories that tries to describe spiritual experiences. Religion is, in part, spirituality in the past.
Whether it is Moses at the burning bush, the four who entered the PaRDeS, or the ecstatic expressions of Chasidic insight, Jewish "religion" is made up of what we now call "spiritual" experience. So why is that so often lost?
So why is the fire of the burning bush so often stamped out in our synagogues? We need to keep the fires burning....