The earth’s atmosphere is a mixture of gases which includes water vapour. We cannot see it but we can surely feel it, like when the air is dry or when it is excessively humid. Water vapour enters the atmosphere because of evaporation of water on the surface, particularly the ocean surface. On the other hand, if the vapour condenses, water falls out of the air. The most common manifestation of the condensation process is rain or snow, but it can also result in the formation of dew.
The atmosphere’s capacity to hold water vapour decreases with temperature. When the temperature falls below a threshold, called the dew point, the moisture has to condense back to water. Early in the morning, or even at late night, objects near the ground lose heat. The nearby air also gets cooled and when its temperature falls below the dew point, moisture condenses on the surface of these cold objects in the form of water droplets that we call dew. A calm, clear and humid atmosphere is favourable for the formation of dew. The surfaces on which dew forms are those which are colder than their surroundings such as plant leaves, grass blades, flowers, metal railings, car tops and window panes. As the sun begins to rise, the dew droplets begin to evaporate and disappear fast.
The processes of dew formation and rain are essentially similar, in that rain involves condensation of vapour on what are called cloud condensation nuclei. But rain falls from a height, while dew does not fall, it just forms on a cold surface. We need rain to quench our thirst and grow our crops, but at times it can be harsh and destructive. Dew is always fresh, soft and mild, pleasing to the eye, delicate, gentle and so fragile.
No wonder then that in the Old Testament, dew has been looked upon as a reminder of God’s tender mercies. The first reference to dew in the Bible comes in the story of Isaac, Jacob and Esau. Isaac blesses his son Jacob, thinking that he is Esau, thus: “May God give you of heaven’s dew and of earth’s richness, an abundance of grain and new wine” (Genesis 27:28). And when he realizes what he has done, he says to Esau: “Your dwelling will be away from the earth’s richness, away from the dew of heaven above” (Genesis 27:39).
When the Israelites received their first manna from heaven, it was preceded by dew. Exodus 16:13-14 says: “That evening quail came and covered the camp, and in the morning there was a layer of dew around the camp. When the dew was gone, thin flakes like frost on the ground appeared on the desert floor.” What a surprise it must have been for the people who had gone to sleep the previous night fretting and grumbling against the Lord, to get up and see their surroundings covered with a carpet of lovely fresh dew. From the physical point of view, dew was perhaps necessary to moisten the dry desert soil so that when people picked up the manna it would be free of dry soil particles adhering to it.. “When the dew settled on the camp at night, the manna also came down” (Numbers 11:9). But surely the dew was a sign from God for his complaining and worried people, that whatever happened, wherever they went, he would never leave them alone nor forsake them.
Moses began his farewell song and message to the people he had led to the promised land, with these words: “Let my teaching fall like rain and my words descend like dew, like showers on new grass, like abundant rain on tender plants” (Deuteronomy 32:2). Later when he blessed the tribes of Israel, he said about Joseph, “May the Lord bless his land with the precious dew from heaven above and with the deep waters that lie below” (Deuteronomy 33:13). And in his final blessing to Israel, “So Israel will live in safety alone, Jacob’s spring is secure in a land of grain and new wine, where the heavens drop dew” (Deuteronomy 33:28).
In any land, water is what sustains all living beings and makes the soil produce food. But where water is scarce, dew can indeed be a precious source of water, and Moses traces that source to heaven. This has a confirmation later in the story of Job, when God himself speaks through the whirlwind and confronts Job with some gruelling questions and he asks Job “Who fathers the drops of dew?” (Job 38:28).
There is an interesting episode in the Bible involving dew. The Israelites had again done evil in the eyes of the Lord, and he had punished them by handing them over to the power of Midian. The Israelites were made to suffer so much by the oppressive and ruthless Midianites, that they cried out to the Lord for help. The Lord then chose a simple man named Gideon to launch an attack on the Midianites and crush them. Gideon was having his doubts about his own strengths and he asked for a reassurance. He said to God, “look, I will place a wool fleece on the threshing floor. If there is dew only on the fleece and all the ground is dry, then I will know that you will save Israel by my hand, as you said.” And that is what happened. Gideon rose early the next day; he squeezed the fleece and wrung out of the dew, a bowlful of water. Then Gideon said to God, “Do not be angry with me. Let me make just one more request. Allow me one more test with the fleece. This time make the fleece dry and the ground covered with dew”.That night God did so. Only the fleece was dry; all the ground was covered with dew (Judges 6:36-40). It is significant that God did what Gideon wanted him to do, not once but twice, letting the dew form either on the fleece or on the ground selectively. To me it appears that this was God’s way of showing that he can bestow his mercy selectively and that we should not take it for granted. As he had said to Moses, “I will have mercy on whom I will have mercy” (Exodus 33:19).
Dew is a sign of plenty, as Job says when he recounts his better days. He had then thought that “My roots will reach to the water, and the dew will lie all night on my branches” (Job 29:19). When the Lord blesses the city of Jerusalem, he talks about dew. “The seed will grow well, the vine will yield its fruit, the ground will produce its crops, and the heavens will drop their dew” (Zechariah 8:12). The prophet Micah makes this prophecy about the ruler to come from Bethlehem: “The remnant of Jacob will be in the midst of many peoples like dew from the Lord, like showers on the grass” (Micah 5:7). There is another similar promise, “I will be like the dew to Israel” (Hosea 14:5).
When blessings are withheld, it is like the absence of dew. This is how the Lord blames the people, “Therefore, because of you the heavens have withheld their dew and the earth its crops” (Haggai 1:10). Again, this is how David laments upon Saul’s death, “O mountains of Gilboa, may you have neither dew nor rain, nor fields that yield offerings of grain . For there the shield of the mighty was defiled, the shield of Saul, no longer rubbed with oil” (2 Samuel 1:21). Elijah had said. “As the Lord, the God of Israel, lives, whom I serve, there will be neither dew nor rain in the next few years except at my word” (1 Kings 17:1).
Rains are at times accompanied by thunder and lightning, but dew comes silently and gently in the night. “A king’s rage is like the roar of a lion, but his favor is like dew on the grass” (Proverbs 19:12). Dew has a freshness and Psalm 110:3 likens it to the freshness of youth. “Your troops will be willing on your day of battle. Arrayed in holy majesty, from the womb of the dawn you will receive the dew of your youth.”
Dewdrops form at night and in the early hours of the morning, but they cannot stand the sun’s heat. As the sun rises and spreads its heat, the dewdrops evaporate and they are no longer to be seen. The Bible recognizes this fact and uses the example of dew to describe the fragility of life and worldly things. “What can I do with you, Ephraim? What can I do with you, Judah? Your love is like the morning mist, like the early dew that disappears” (Hosea 6:4). The simile is applied again to idolaters, “Therefore they will be like the morning mist, like the early dew that disappears, like chaff swirling from a threshing floor, like smoke escaping through a window” (Hosea 13:3).
There is however, one particularly difficult reference to dew in the book of Daniel, chapters 4-5, where Daniel interprets the dream of King Nebuchadnezzar. The interpretation comes true and it is said about Nebuchadnezzar that “he was driven away from people and ate grass like cattle. His body was drenched with the dew of heaven until his hair grew like the feathers of an eagle and his nails like the claws of a bird. until he acknowledged that the Most High God is sovereign over the kingdoms of men and sets over them anyone he wishes.” This dew is obviously of a different kind.