Many people have often had the experience, when they read or hear something, of feeling that it is just what they would have wanted to say.
A person can also pray on a profound level and the words of the prayer book mirror exactly his own thoughts and desires.
He himself flows together with the prayer service, ascending and descending from psalm to psalm, from blessing to blessing, from one level of reality to another, moving with the services like a traveler journeying through various vistas.
He is on Mt. Moriah, present at Abraham's sacrifice of Isaac;
he is then in the Temple, offering sacrifices;
he rises and praises God together with the heavens;
he stands at the Red Sea as he recites, "Then sang Moses";
he joins the angels in proclaiming God's holiness, rising with the ophanim in a thunderous chorus facing the seraphim;
he enters into a state of oneness when he recites the Sh'ma;
he surrenders everything to God when he states "and you shall love";
and he stands before God with complete self-effacement in the Sbmoneh Esreh.
In such prayer, the person praying and the words being prayed are one.
There is no longer a dividing line between one's inner reality and one's outer expression, between communal ritual and the personal voice of the heart.
–Rabbi Adin Steinsaltz
Adapted from "Prayer," in The Thirteen Petalled Rose (new edition) by Rabbi Adin Steinsaltz