How many biblical plagues are associated with the story of the Exodus from Egypt ? Can you name them? All of them? In order?

Most people remember the final plague of the killing the firstborn (both male children and livestock) that prompted the Exodus. That’s one. But how many more are there?

Would it shake your confidence to learn that the Book of Exodus isn’t the only plague list in the Bible? Don’t believe me? There's only one way to find out.

Let’s start with the list of plagues most of us are familiar with in the Exodus story.

If you got them all, excellent job! You finished listing all ten plagues in order. And that's typically the correct answer.

But take another look. Did you think the first plague was turning the Nile River to blood? If so, why does our list use the general word "water"? Let's take a closer look at this plague specifically and ask what water is being transformed and who is doing the transforming.

Notice the distinction? While the initial threat in Exodus 7:14–18 was for Moses to use his staff to turn the Nile River into blood, in Exodus 7:19 Aaron is told to use his staff to turn all of the water in Egypt—even the water in storage jars—into blood.

So what is going on? Are Moses and Aaron collaborating so that Moses is responsible for only the Nile, while Aaron transforms everything else? Since all the water in Egypt would necessarily include the Nile, Moses’s role feels a bit redundant. Perhaps the ending will help:

If you read the two parts of Exodus 7:20–24 separately as indicated (plain vs. bold text), you'll observe one story about Moses turning only the Nile to blood and the people having to dig alongside of the Nile for new water (the part in plain text), combined with a separate story about Aaron turning all the water in Egypt to blood and the magicians duplicating it (the part in bold text).

Either the story in Exodus 7:20–24 is highly contradictory, or, the story of the first plague is a combination of two similar stories from two separate sources. This is not uncommon in the Bible. In the Torah, scholars use consistent themes and specific details to distinguish the different sources of stories that they see as having been edited together.

Believe it or not, the first plague is only the first part of a larger process of intertwining various "plague" traditions together. And this combination of various traditions from different sources of is actually seen throughout the Torah. Here, two sources make up most of the narrative:

1. Moses is the primary actor and Aaron is in the background or absent. This is called the J or Jahwist/Yahwist source.
2. Aaron is the primary actor and Moses merely talks. This is called the P or Priestly source.

The letters refer to the classic Documentary Hypothesis, which demonstrates that four sources—J, P, E (for Elohist), and D (for Deuteronomist) were edited together to make up the Torah we have today.

(For example, this explains why there are two markedly different creation narratives in Genesis. In chapter 1, Adam is created after all of the animals in Genesis 1:27; but in chapter 2, Adam is created before all of the other animals in Genesis 2:7. Note that after Adam is created in Genesis 2:7, Genesis 2:19 says, "So out of the ground the LORD God formed every animal of the field and bird of the air and brought them to the man..." It also explains why two different numbers were given for how many animals were on Noah's ark. Genesis 6:19 says, "You shall bring two of every kind into the ark...they shall be male and female," while Genesis 7:2 says, "Take with you seven pairs of all clean animals, the male and its mate; and a pair of the animals that are not clean, the male and its mate." These were two similar, but different flood stories originally from two different sources, that were later woven into a single story. It explains the clearly contradictory information given only verses apart in each story.)

The same thing is happening here with the story of the ten plagues. Once you look at the plagues as originating from two different sources, things begin to make sense, and you begin to notice certain details. For instance, notice that Exodus never states that there were ten plagues, only that God "will multiply my signs and wonders in the land of Egypt" (Exodus 7:3). Below is a table that breaks the plagues down by source:

Scholars argue that the J source originally included eight plagues, while the P source originally included only five. And because three plagues overlap—1) water turned to blood, 2) frogs, and 3) the killing of the firstborn—a total of ten separate plagues results when combined.

Now, the question we should all be asking is: how do scholars know that these plagues originally came from different sources? It would be helpful to have one of the original lists of plagues before it was combined with the other, preferably from a biblical author. That would certainly go far toward demonstrating that the biblical "Ten Plagues" were originally from two different lists.

Well, we're in luck. As it turns out, Psalm 78 preserves a poetic telling of Israel’s history that focuses on the Lord’s repeated interventions on their behalf, including ... you guessed it—a list of plagues "when he displayed his signs in Egypt" (Psalm 78:43). When we observe this list of plagues, and compare it to the list in Exodus, we get the following:

Psalm 78 is very similar the J list, specifically mentioning eight of the plagues mentioned in Exodus 7–12: rivers to blood, flies, frogs, locusts, hail, cattle, thunderbolts, and the death of the firstborn. However, it leaves out two plagues from the P source (gnats and boils) and one from the J source (darkness).

Fortunately for us, there is yet another list of plagues in the Bible. Psalm 105 is also a poetic retelling of Israel’s history and the Lord’s intervention. Adding this to our table reveals the following:

If only to add to the confusion, Psalm 105 is the only list that doesn’t begin with water to blood. It starts with darkness, which is plague nine in Exodus 10, and which isn’t even included in Psalm 78. But then we see many of the expected plagues, though not all of them, including waters turned into blood, frogs, flies, gnats, hail, lightning/storms, locusts, and the death of the firstborn.

But one thing we can deduce from these three lists is that Psalm 78 and Psalm 105 appear to preserve a different number of plagues, and in a different order. These two separate lists may have served as sources for editors, who later combined the two traditions to create a more well-rounded list of ten plagues that progressed in a fitting order.

So, to answer our question of how many plagues there are, the answer depends on which list you use and how you divide it. The editor-redactors of the final version of Exodus ultimately crafted a set of Ten Plagues, neatly arranged in three evenly-matching triads, capped by the death of the firstborn.

So yes, we can say that there are TEN plagues as we have them today. However, this final list is likely the product of multiple sources that were redacted together to create a story filled with meaning and symbolism for the Jewish people. Remember, history is different for us today than it was for those in antiquity. While precise details and facts are important to us in the modern world, they were not as important for those in the ancient Mediterranean and southwestern Asia. Even Thucydides, one of the founders of historiography, wrote most of the speeches in his works, giving them his own sophistic flair—including even Pericles’s famous funeral oration. They wrote histories to teach future generations important lessons using the events of the past.

So what lessons do the stories of the plagues convey to the audience? Both Psalms 78 and 105, as well as Exodus 7–12 preserve the belief that the Hebrew God will intervene on Israel’s behalf, and that God will use every tactic at his disposal, from manipulating the weather, to destroying livestock and livelihoods, to slaughtering an entire generation of Israel's oppressor's firstborn children, in order to make his point. It seems like a harsh and brutal punishment from the deity, but in an ancient world dominated by monarchs, slavery, and imperial powers, the actions of the deity intriguingly reflect the practices of the time—something most religious texts share in common.