How can we stop the evil inclination from interfering with our ability to pray properly?
(30,14) “Rather, the thing is close to you very much (מאד), in your mouth and in your heart, that you may do it.”
Since thought precedes speech, the posuk should have said “in your heart and in your mouth”! However, the Torah is hinting to us here how to deal wisely with the evil inclination, by guarding against even the least serious wrongdoing in order not to be led into doing a much more serious transgression, G-d forbid.
Because the midrash on the posuk “and G-d saw everything that He had made, and behold it was very good (טוב מאד)” (Bereishis 1:31) teaches that the word מאד refers to the evil inclination. And it is the way of the evil inclination to first entice a person to sin in a light matter and afterwards to seduce him to sin in a more serious matter, G-d forbid.
Thus, it first seduces a person in the matter of eating - treating the matter of eating with excessive indulgence, and afterwards when he is praying it persuades him to pray quickly in order to get to his eating sooner. But if a person prevails against the evil inclination in the matter of eating, it will have no hold over him when he is praying.
This is the meaning of the posuk: “Rather the thing is close to you, very much” - this is the evil inclination, “in your mouth” - endeavoring to make you excessively desire food. But if you do not yield to the persuasion of the evil inclination and curb your desire for food, it will have no control over you when you pray, and thus “in your heart that you may do it” - you will be able to pray properly, prayer being the service of the heart.