Definition for Mouth in Scripture
Mouth (God the Father in Scripture has one; the incarnate Son of God has one)
What Does the Word Mouth Mean in Scripture?
Using the analogy of a master boat designer will help to explain. In our analogy, a particular designer possesses the knowledge to design and build the best boat in the world. His knowledge consists of thoughts within his brain. Everything is in his head. Unless and until those thoughts are sent out employing some form of expression/gifting, they remain just that — thoughts. The designer expresses (sends out) his thoughts when, for example, he: 1) goes out and builds the boat; 2) verbally tells someone how to build this boat; 3) draws diagrams of how to build the boat; and/or 4) writes a “How-To” book about building the best boat in the world. Expressions are not limited to spoken words. Any expression that sends out a thought can be classified as a word, whether verbal or otherwise. With that in mind, let us proceed with our definition of the meaning of mouth in Scripture.
The Mouth of God
God does not have a physical mouth. So, when we read in Scripture of the mouth of God (e.g., 1 Kgs 8:15), are we to interpret it as a metaphor that helps us understand who or what is doing the communicating? Let’s apply our understanding of being sent to the Trinity. In Scripture, it is only the Word of God (Jn. 3:17; 5:23) and the Holy Spirit (Jn. 14:26) who are ever described as being sent. The Father is never described as such. The Father is always the one who sends. The Father is not expressed; the Father is the one who expresses, i.e., sends. In Scripture, it is that which sends out that is identified as the mouth. The Father sends the Son — the Word of God. When the Word is sent, so also is sent the Breath, i.e., the Holy Spirit (cf. Jn. 20:21-23; Is. 55:10-11). When a human wishes to say something, the words cannot be sent out without the accompanying breath. Scripture tells us “man does not live by bread alone, but that man lives by everything that proceeds out of the mouth of the Lord” (Deut. 8:3).
The Breath from the Mouth Dwells in the Heart
The heart of God on fire, i.e., the Holy Spirit, dwells in our spiritual hearts. Some theologians do not describe God as having a Heart. As a result of what has already been covered in this book, we should already know intuitively that God indeed has a Heart. The Heart is that which is Truth, knows that Truth, and Loves what is known. Hence, the Heart of God is the undivided unity of all Three Persons of the Trinity.
However, Durrwell writes, “It is there, in our hearts, in the intimate depths of the believer, that the Spirit chooses his dwelling. In God himself the Holy Spirit of God reaches the ‘depths’ (cf. 1 Cor. 2:10). He is, as it were, the heart of God.” St. Robert Bellarmine, Theologian and Doctor of the Church, is known as the father of apologists. In his three-volume work titled, Disputationes de Controversiis Christianae Fidei adversus hujus temporis Haereticos, Bellarmine tells us the Holy Spirit is the heart of God — is the Spirit of God. St. Hildegard tells us, “In the heart of the radiant Father [SML] … burns the Holy Spirit.”
Jesus tells us, “[O]ut of the abundance of the heart the mouth speaks” (Mt. 12:34). Mouth in Scripture refers to that which fruitfully expresses (sends out) the overflow of the heart. Not only the mouth sends out, but it also takes in (in the form of Actual grace) whatever is to reach the heart. Matthew writes, “Do you not see that whatever goes into the mouth passes into the stomach, and so passes on” (Mt. 15:17)? Does Mt. 15:17-19 contradict the previous sentence? When talking about Actual Grace, the answer is No! See explanation in Endnote.
Every thought that is sent, is sent somewhere. Every expression has a destination to which it is directed. What was the Father’s intended destination for His expression of the Word in the force of His Breath? The answer is — creation.
St. Thomas Aquinas writes, “Now the craftsman [the Father] works through the word conceived in his mind, and through the love of his will regarding some object. Hence also God the Father made the creature through His Word, which is His Son; and through His Love [which is associated with the heart/spirit], which is the Holy [Spirit].”
As we said previously, all expressions in Love are fruitful because God is eternally fruitful. The Father fruitfully expressed the Word through the power of His Breath, and that expression produced the fruit of creation. Hence, we read in Scripture, “So shall my word be that goes forth from my mouth [God the Father]; it shall not return to me empty, but it shall accomplish that which I purpose, and prosper [be fruitful] in the thing for which I sent it” (Is. 55:11).
We can conclude that the fruit, which is produced by the expression of the Word by the force of the Father’s Breath, will return to that same mouth of God (the Father) who expressed it, where it will be breathed in and become one with God — thus entering into the Trinitarian dialogue (cf. 2 Pt. 1:4). The concept of inhaling and exhaling the Breath through the mouth, can also be understood in the light of the Eucharistic discourse (Jn. 6:48-70). Jesus tells the crowd that his flesh is real food and his blood is real drink. He breathes the Breath through his mouth (his body and blood in the Eucharist), and we inhale the Breath when we receive Him in the Eucharist through our mouth/body.
The Mouth of Man
In my view, the use of mouth in the lexicon of Scripture applies to God the Father and rational man — including the incarnate part of the Second Person of the Trinity, the Word of God. In Scripture, I believe the mouth is used to denote that through which the overflow of the spiritual heart is sent out. Mouth also identifies the means by which is taken in that which will feed the inner heart with either lust or grace. For man, the mouth is the entire body. It breathes in that which can either enlighten (through the grace of the Holy Spirit) or darken (darken with pride and lust).
Depending upon the individual circumstances, various parts of the body may play a more or less prominent role in a particular expression. For example, while the biological mouth might be the most prominent sense-able component of an expression of praise to God, the entire body is involved. As JP II wrote, “The body speaks not merely with the whole external expression of masculinity and femininity, but also with the internal structures of the organism, of the somatic [the entire body and its aggregate parts] and psychosomatic [relating to the mind/mental] reaction.”
When God speaks or sends forth His Word, He does it with His mouth (Is. 55:11). When man speaks a sense-able and meta-sense-able word (both components are continuously contributing to the total expression), it is his entire mouth/body, through which the word/expression is sent out.
Let’s look at a passage that will show us that God is frequently not referring to the literalistic biological mouth when using the word in Scripture. While the entire scriptural mouth (the body) of a person contributes to an expression, verbal expression through the literalistic biological mouth may or may not occur. God addressed himself to the Israelites concerning the commandments and the decrees of the Law. He said, “For this commandment which I command you this day is not too hard for you, neither is it far off ... the word is very near you; it is in your mouth [your body] and in your heart [your spirit] so that you can do it” (Deut. 30:11,14). We do with our entire body — not just the biological mouth. JP II writes, “In the text of the prophets the body speaks a ‘language.’” From where does speech exit the body? The mouth.
According to St. Hildegard, virtues work through the body and soul together; “a virtue is a divine quality that … fully incarnates itself [SML].” What does this mean? It means: as the heart is purified, so also is the body. We discussed this earlier. The higher powers of the soul (where the Holy Spirit dwells) are not fenced off from the lower powers (which control the body). Why is this necessary? In its role as the mouth of the overflow of the spiritual heart, the body must accurately express (both sense-ably and meta-sense-ably) virtuous acts which will bear good fruit. West tells us that the body simply gives expression to the experiences of the heart; the spirit expresses itself in the language of the body.
 It could potentially lead to theological error to believe that the Holy Spirit is ‘sent’ in the same manner as the Son is sent. Only the Son is expressed. The Holy Spirit proceeds. Having issued that proviso, the current context is sufficient to understand the meaning of the ‘mouth’ of God.
 Durrwell, Holy Spirit of God, 36-37.
 cf. Hildegard, Scivias 35.
 cf. Leen, The Holy Spirit, 32-33.
 Richard Payne and Stephen Payne, “Saint Robert Bellarmine-Part II,” Saints Alive (Arcadia Films, aired November 16, 2011), Saints Alive is a TV program that airs on EWTN. In this series, an actor portraying a saint is interviewed and his or her response is taken directly from the actual writings of the saint.
 Hildegard, Scivias, 363.
 In verse 15:2, the Pharisees are accusing the disciples of defiling themselves because they have not performed the prescribed ritual washing of their hands before eating. The Pharisees are clearly talking about food which is defiled because it was touched by unclean hands, subsequently going through the literalistic biological mouth. So this is the context in which Jesus responds, i.e. whether or not organic food entering the biological mouth and eventually coming out the other end of the body defiles us. This is evident by the wording he uses. In v. 17 he says, “Do you not see that whatever goes into the mouth enters the stomach, and goes out into the sewer. In v. 19-20, Jesus tells the Apostles that adultery, fornication, theft, etc. coming out of the mouth are what defiles us. In a later discussion concerning the “mouth,” we will discuss the scriptural basis for believing that the mouth/body play a role in both taking in, and sending out that which truly defiles.
 Aquinas, Summa Theologiae, I, q. 45, a. 6.
 cf. CCC, n. 460.
 Fr. Michael Gaitley, The ‘One Thing’ Is Three: How the Most Holy Trinity Explains Everything, (Kindle Locations 538-553). Marian Press. Kindle Edition.
 John Paul II, in his general audience of Sept. 5, 1984, “Responsible Parenthood Linked to Moral Maturity,” Theology of the Body, ©Libreria Editrice Vaticana (Third Millennium Media L.L.C., The Faith Database L.L.C., 2008), n. 1.
 Pope John Paul II, in his general audience of January 12, 1983, “The Language of the Body in the Structure of Marriage,” Theology of the Body, ©Libreria Editrice Vaticana (Third Millennium Media L.L.C., The Faith Database L.L.C., 2008), n. 7.
 Hildegard, Scivias, 345.
 Ibid., 37.
 West, Theology of the Body Explained, 94.
 Ibid., 382.