The ultimate purpose of prayer is to raise the Divine spark which enables real communication to take place.
It is an awakening of the spiritual in us and letting it carry us to the utmost of our capacities to cling to God in "devekut."
This task cannot be done only through mental effort.
There has to be an experience in the heart.
This awakening of the innermost heart substance is the most important aspect of prayer.
-Rabbi Adin Steinsaltz
From In the Beginning, "Prayer as Sacrifice," by Rabbi Adin Steinsaltz