“As he that taketh away a garment in cold weather, and as vinegar upon nitre, so is he that singeth songs to a heavy heart.” Proverbs 25:20
“For though thou wash thee with nitre, and take thee much soap, yet thine iniquity is marked before me, saith the Lord God.” Jeremiah 2:22

Vinegar upon nitre?? Washing with nitre?? Too often, I fear, we read over such texts, without giving due attention to their Spirit-inspired symbolism. And in this case we will not understand the symbolism without some knowledge of what nitre is (also spelled niter). It is a mineral, yes, but what exactly are its pertinent features? To that question we now turn our attention.


Water, air, fire, and earth were considered by the Greeks as the four basic building blocks (elements) of the ancient world. Today, however, we understand the elements that make up our world to have greater complexity and detail than as described by the ancients. What the Greeks termed “earth”—defining the actual composition of our world—is made up of more than 3,000 minerals, each with its own unique characteristics.

The earth’s crust is composed of minerals—naturally occurring solids that have a distinct crystal structure and chemical composition. From their aesthetically beautiful and orderly crystal structure to their many and varied uses, minerals are a fascinating and signif­icant “character” in, what our Belgic Confession calls, God’s “most elegant book” of creation. According to their unique structure and chemical composition, min­erals are generally classified into the following eight cat­egories:

1) Native elements—a group of approximately twenty “un-reactive” elements generally found unbond­ed to other elements. Native elements include the precious metals of copper, silver, gold, and platinum.

2) Sulfides—of which the vast majority of our “ores” are composed.

3) Oxides (and hydroxides)—of which many “ores” and natural gemstones are composed.

4) Halides—from which we obtain our natural salts.

5) Carbonates (including nitrates and borates)—from which we obtain the materials to make our ce­ment. Carbonates include natural substances such as marble and limestone rocks.

6) Phosphates—from which we obtain phosphorus to make fertilizers.

7) Sulfates—from which we obtain the materials to make plaster.

8) Silicates—comprise 96% of the earth’s crust. Dominant minerals in this group are quartz (abundant component of sand), mica, and talc.

To examine each of these groups in detail would be a worthwhile study of the beauty and power found within the creation. They testify of the beauty, wisdom, and power of our Creator. The Lord willing, we plan to look more closely at some of these groups, but for the remainder of this article, we will consider the carbonate group, examining particularly the mineral nitre, which we have seen is specifically mentioned in the Scriptures.


The texts quoted earlier are the only two places the word “nitre” is used in all of Scripture. An understanding of the word “nitre” helps us understand the teaching of Proverbs 25:20. Following the hermeneutical principle of using other passages of Scripture to help interpret a passage, we find that Jeremiah 2:22 provides good direction in ascertaining the meaning of the word “nitre” and, therefore, sheds light on Proverbs 25:20. Let us see how this is so.

One might be inclined to assume that the nitre men­tioned in Holy Scripture is a common mineral, namely, saltpeter (potassium nitrate) or Chile saltpeter (sodium nitrate). The word “niter” today refers to saltpeter—a substance that has been mined in large quantities in the arid deserts of Chile and is useful in making fertilizer and explosives. Interestingly, however, the word “niter” did not always refer to saltpeter. It was only as com­pounds used in explosives became more widely used and known among Europeans during the Middle Ages that the word “niter” began to refer to saltpeter—the important nitrate mineral used in making explosives. This is borne out by the following word study:

C. 1400: “native sodium carbonate” (a sense now obsolete), from Old French nitre (13c.), from Latin nitrum, from Greek nitron, which is possibly of Eastern origin (compare Hebrew nether “carbonate of soda;” Egyptian ntr). Originally a word for native soda, but also associated since the Middle Ages with saltpeter (potassium nitrate) [emphasis mine] for obscure reasons; this became the predominant sense by late 16c.1

Apart from the word origin, an understanding of the chemical properties of niter and the chemical properties of the common minerals found in the earth help us understand the symbolism of the text. Distinguishing between the properties of the carbonates [soda] and nitrates [saltpeter] will be helpful.

Carbonates are widely found in the earth’s crust as limestone. The mineral name for pure deposits of calcium carbonate is calcite.

Other familiar forms of calcite are the stalactite and stalagmite deposits found in caves and the travertine deposits along the mouths of spring waters in places like Mammoth Hot Springs of Yellowstone National Park. Calcite is used primarily in the manufacturing of cement and lime for mortar. Carbonates are known for their intense and vivid reac­tion with acids. When acids are combined with carbon­ates, the carbonate compound breaks down, releasing a molecule of one carbon and two oxygen atoms (carbon dioxide gas). The rapid escape of the carbon dioxide from the slurry of acid and mineral deposit produces a bubbling and foaming mass.

Nitrates, on the other hand, are less commonly found in the earth’s crust. Common forms of nitrates are ei­ther soda niter (sodium nitrate; also known as Chile saltpeter) or plain niter (potassium nitrate; also known as saltpeter). Both forms of niter are used in fertilizers and explosives (gunpowder, for example, is made from a mix of sulfur, charcoal, and saltpeter). Because of the strength of the nitrogen-oxygen bond, nitrates are less easily decomposed by acids than are carbonates—and consequently, nitrates have little reaction in the presence of acids.

While the word “niter” today refers to saltpeter, it does not make much sense to understand the biblical reference to niter as a reference to saltpeter. One reason for this is that there is no significant reaction between saltpeter and vinegar, as suggested by the text. There­fore, we are led to believe that niter, as used in Proverbs 25:20, does not refer to a nitrate compound.

Biblical scholars agree that the Hebrew word “ni­ter” used in these passages refers to common substanc­es found in Israel and in Egypt. In Egypt “neter” re­ferred to the mineral compound sodium carbonate (which came from the Egyptian salt lakes), whereas in Israel “neter” more likely referred to potash or po­tassium carbonate (made from the ashes of plants).[1] Neter, as sodium carbon­ate, was extracted from watery beds in the Middle East and was common­ly used to make laundry soap—thus the reference in Jeremiah 2:22 to nitre and the attempt to wash oneself thoroughly with it.

If one mixes vinegar and niter, a chemical reaction occurs. Niter, or soda ash (sodium carbonate), is not likely available in your home, but a similar compound, sodium bicarbonate (baking soda), is. As long as you are willing to clean up the mess, it would be entertaining to mix a cup of bak­ing soda (sodium bicarbonate) and a cup of vinegar in a bowl in your kitchen and observe the reaction. The so­dium bicarbonate will violently effervesce (fizz or bub­ble) as carbon dioxide is released in the reaction. Niter, when mixed with vinegar, will effervesce in a similar fashion to your household baking soda.

Niter (sodium carbonate), as mentioned in Jeremiah 2:22, is used in making laundry soap. But pouring vin­egar on sodium carbonate (niter), while making a fizzing display similar to that of the reaction of baking soda and vinegar, would ruin the niter as an agent to make laundry soap.

With these things in mind, the proverb makes more sense: “As he that taketh away a garment in cold weath­er, and as vinegar upon nitre, so is he that singeth songs to a heavy heart” (Prov. 25:20). If I take away a gar­ment from my friend in cold weather, I am not helping him stay warm and comfortable. In fact, I am making things worse by removing the very thing that could have helped him. If I pour vinegar on nitre, I will have a violent fizzing display, but no profitable products. The nitre that could have served as an effective laundry de­tergent or soap (see Jer. 2:22) is now a ruined mess. The final mixture of vinegar and nitre is nothing more than a salt-watery substance that has no profit at all, but to be thrown out. Thus, do Solomon and Jeremiah, under the inspiration of the Spirit, use this fascinating little creation of God to make a real spiritual truth come alive before our eyes.

Think for example of attempts to comfort the heavy-hearted, grief-stricken saint with silly jokes, mundane stories, or frivolous jesting. Such “singing songs” only worsens the pain (similar to making my friend from whom I took the garment colder—which, in turn, is like the violent but useless reaction of mixing the vinegar and niter). With such carnal mirth (singing songs) there is no comfort to the hurting saint. With such attempts, it may be said of us “what miserable comforters” we are!

May we learn from such figures in Scripture to be true and blessed comforters. A simple gesture of godly compassion brings true comfort—comfort void of car­nal mirth or empty speech. And so, let us mourn with those who mourn (shed a tear with them, empathize with them). For it is better to go to the house of mourn­ing than to the house of feasting (Eccl. 7:2). And let us bring an appropriate Word of God to the grieving saint, as God’s Word is profitable in every situation of life. For God’s Word is the means that He has ordained to com­fort and soothe those who experience difficult trials. It is essentially the only word that I can bring to uplift a fellow saint. Regardless if I have gone through a simi­lar experience myself or not, when I bring God’s Word it comforts the soul of God’s people. This is because God’s Word, though despised and considered foolish­ness to the world, is the power of God to comfort His people. “Comfort ye, comfort ye my people, saith your God. Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned” (Is. 40:1–2a). Thanks be to God for His unfailing Word—for Christ and the certain victory that is declared therein!

And thanks be to God for His Word in the psalms, from which we may sing comforting words to the heavy-hearted. These precious psalms address the many struggles of the child of God and bring blessed com­fort. “Many are the afflictions of the righteous: but the Lord delivereth him out of them all” (Ps. 34:19). May God, therefore, preserve faithful psalm-singing in our midst—to the edification of God’s people and the glory of His blessed name! And may God bless us with the grace and wisdom to truly comfort those who mourn and to be a blessing to our grieving brothers and sisters in Christ.

1  https://www.etymonline.com/word/nitre.