A few verses from Sri Aurobindo

Mysticism, or Spirituality, is about transformation of consciousness.
About re-defining one's relationship with reality.
With a radical & fundamental re-definition of self & reality itself.
THIS has to be understood. Then one can easily percieve that there is no fundamental conflict between mysticism & rationality: there cannot be.
The conflict is only between a Jesus who HAS grasped this new truth, this new view - and the rest of humanity, which hasn't.
Man enlarges the very context of his being & existence, in mysticism; rather, he adds to the context: he discovers new contexts to his own being & existence: he sees himself from new perspectives.
He discovers unsuspected truths about himself, his very identity, his powers of apprehending truth.
It's not (primarily) about HOW to deal with reality - which is of crucial importance nevertheless - but WHAT is reality itself.
It's the discovery of a totally different face or aspect of reality.
And that's why, Sri Aurobindo wrote (I'm quoting out of Fritjof Capra's "The Tao of Physics"): "All things in fact begin to change their nature & appearance; one's whole experience of the world is radically different ... There is a new vast & deep way of experiencing, seeing, knowing, contacting things."
The whole objective is to EXPERIENCE REALITY IN A TOTALLY DIFFERENT WAY: & the importance of the objective lies in that in mysticism man seeks to experience ULTIMATE REALITY: it is his direct, total EXPERIENCE of reality in its very essence, its very root.
It is not UNDERSTANDING reality in the sense of being able to formulate, mathematize, & explain the processes of its working, to explicate its laws & so on: but KNOWING REALITY - TO EXPERIENCE WHAT IT ESSENTIALLY, FUNDAMENTALLY IS, in its TOTALITY, as ONE, COMPLETE WHOLE.
Not description or analysis, but plain & simple experience of the totality of reality by the totality of our being.

Here are a few lines from "Savitri", Aurobindo's magnum opus, which I've been trying to read for a while.
It's very heavy, very difficult to read at one stretch, and my own effort is broken & a little disjointed because I've to pay attention to other theoritical subjects which are of greater immediate, pressing importance.
But these lines are just fabulous:

Our souls can visit in great lonely hours
Still regions of imperishable Light.
All-seeing eagle-peaks of silent Power
And moon-flame oceans of swift fathomless Bliss
And calm immensities of spirit space.
... ... ....
In the unfolding process of the Self
Sometimes the inexpressible Mystery
Elects a human vessel of descent.
... ... ...
A breath comes down from the supernal air,
A Presence is born, a guiding Light awakes,
A stillness falls upon the instruments:
Fixed, motionless like a marble monument,
Stone-calm, the body is a pedestal
Supporting a figure of eternal Peace.
... ... ...
Or a revealing force sweeps blazing in;
Out of some vast superior continent
Knowledge breaks through trailing its radiant seas;
And Nature trembles with the power, the flame.

Or,

In moments when the inner lamps are lit
And life's cherished guests are left outside,
Our spirit sits alone & speaks to its gulfs.

Or, these poetic lines of unparalleled beauty glorifying the heroic in man:

His days were a long growth to the Supreme.
A skyward being nourishing its roots
On sustenance from occult spiritual founts
Climbed through white rays to meet an unseen Sun.
His soul lived as eternity's delegate,
His mind was like a fire assailing heaven,
His will a hunter in the trails of light.
An ocean impulse lifted every breath;
Each action left the footprints of a god,
Each moment was a beat of puissant wings.

There are a lot, lot more, but I'll put them up or just express my thoughts on them later.