The 'mystery' of prayer?

(From Octavius Winslow's, "The Axe Laid at the Root")

That there is much of wondrous mystery yet to
be unraveled in relation to this holy exercise
of prayer, we readily admit.

How prayer operates upon God we know not.

That it can effect any alteration in His purpose,
or change His will, or afford Him information, no
one for a moment supposes.

And yet, that it should be an ordained medium by
which finite weakness seems to overcome Infinite
strength, and a human will seems to turn the Divine
will, and man's shallow mind seems to pour knowledge
into the fathomless mind of God; that it should halt
a threatened judgment, or remove an existing evil,
or supply a present need; is a marvel in which, like
all others of Divine revelation, I submit my reason
to my faith, receiving and adoring what my reason
cannot, unless I were God, perfectly comprehend.