When a person’s hand or speech becomes an instrument of God’s will, it does not mean that it is the organ itself that is thus being used.
God is acting through the person as a whole.
However, when a person studies Torah, with mouth and mind, he reaches a deeper and more internalized relation with God.
Because there is a certain difference between the mitzvah and Torah study.
The performance of the mitzvah is a means of expressing and fulfilling whatever God wishes to happen in the world.
When my hand gives alms, it means that God desires to sustain this needy person.
I am only a means of accomplishing this.
If God wishes someone to wear tefillin, my hand and head serve to realize this.
If He wants the Chanukah candles lit at a certain moment, my performance of the mitzvah assures that His will is done.
However, when a person studies Torah, there is a more profound factor involved, for the Torah itself is God’s will.
–Rabbi Adin Steinsaltz