Did the Nephilim Survive the Flood? The Second Incursion Theory

There is an awkward problem sitting in plain sight in the Torah. Genesis 6 says the Nephilim were on the earth before the Flood. Genesis 7 says the Flood wiped out all flesh except those on the ark. And then Numbers 13 — hundreds of years and an entire deliverance-from-Egypt later — has the Israelite spies coming back from Canaan terrified, saying, "We saw the Nephilim there... and we seemed to ourselves like grasshoppers" (Numbers 13:33).

If the Flood destroyed the Nephilim, how are there Nephilim again? And who are the Anakim, the Rephaim, and the other giant clans that Israel spends the conquest fighting? The second-incursion theory is the most well-known attempt to answer that puzzle — and it has real strengths, real problems, and real rivals. Below is the case, the alternatives, and an honest assessment.

The Puzzle, Plainly

The tension is worth stating carefully because it is the whole reason the debate exists:

1. Genesis 6:4 — The Nephilim are on the earth "in those days, and also afterward," when the sons of God fathered children by human women.
2. Genesis 7:21–23 — Every living thing that moved on dry ground perished in the Flood; only Noah and those with him on the ark survived.
3. Numbers 13:33 — The spies report seeing "the descendants of Anak, who come from the Nephilim," in Canaan.
4. Deuteronomy 3:11 — Og of Bashan, a king the Israelites defeated, is described as the last of the Rephaim, with a bed thirteen feet long.

So either (a) the Flood did not fully remove the Nephilim problem, (b) the term "Nephilim" is being used more loosely than we think, or (c) something happened after the Flood to produce giants again. The second-incursion theory takes option (c).

The Second-Incursion Theory

Core claim: Genesis 6:1–4 was not a one-time, globally unique event. After the Flood, the same kind of transgression — divine beings crossing the boundary into human women — happened again, on a smaller and more localized scale, producing the giant clans of Canaan: the Anakim, the Rephaim, the Emim, the Zamzummim.

Key advocates: Michael S. Heiser (The Unseen Realm, Supernatural) is the most prominent modern defender. Timothy Alberino develops it extensively in his Nephilim framework, and it is common in the broader alternative-history and "transhumanism as recurrence" literature.

The case for it:

• It takes Genesis 6:4 literally. The verse itself says the sons-of-God event happened "in those days, and also afterward." The second-incursion reading takes "afterward" seriously: the pattern recurred after the Flood.
• It solves the puzzle cleanly. If the Nephilim of Genesis 6 died in the Flood, and the giants of Canaan are the product of a new incursion, then Numbers 13:33 no longer contradicts Genesis 7. The spies saw a second generation, not survivors.
• It fits the supernatural worldview. If the sons of God are divine beings (as argued in the related theory page), they are not destroyed by a flood of water — they are spirit. There is nothing in the text preventing a recurrence, and the wider biblical story treats the spiritual rebellion as ongoing.
• It explains the conquest. Israel's mission to clear Canaan takes on a sharp edge if the Canaanite giant clans are understood as a fresh outbreak of the same Genesis-6 corruption. God's instruction to devote them to destruction is barbaric under a standard "rival tribes" reading; it reads very differently if those clans are a recurrence of the original transgression.

The weaknesses:

• The Bible never explicitly says it. For all its explanatory power, there is no verse that states "the sons of God did this again after the Flood." The second-incursion view is an inference from the puzzle, not a stated fact. Critics argue that's a lot of weight to put on an inference.
• It must explain the "why." If the first incursion ended in worldwide judgment, why would spirit beings try the same thing again? Defenders answer that the rebellion is irrational and persistent, but the question is fair.
• The spies may have been wrong. The report in Numbers 13:33 comes from the ten faithless spies, not from an inspired narrator. Some scholars argue the spies called the Anakim "Nephilim" out of fear — exaggerating — and that the text is reporting their panicked claim, not endorsing it as fact.

The Alternatives

Three other explanations are worth taking seriously.

Alternative 1: Genetic Carryover Through Noah's Line

The simplest human-scale explanation: one of Noah's daughters-in-law carried giant bloodlines, and those genes resurfaced in the generations after the Flood, producing the Canaanite clans.

This is popular in creationist and literalist circles. Its strength is that it needs no supernatural mechanism and keeps everything within the text's family-genealogy logic. Its weakness is that it requires the Nephilim corruption to have survived the Flood through the ark — which sits uneasily with the Flood's stated purpose of wiping out that very corruption, and with God's declaration that Noah alone was "righteous" and "perfect in his generations" (Genesis 6:9).

Alternative 2: A Local, Not Global, Flood

If the Flood was regional rather than planet-wide, the Nephilim could simply have survived outside the flood zone and reappear later.

Some Old Testament scholars take the local-flood reading on textual and ANE-comparative grounds. Its strength is that it dissolves the puzzle entirely. Its weakness is that it runs against the plain reading of Genesis 6–8 ("all the high mountains under the whole heaven were covered") and against the way the New Testament treats the Flood as a universal judgment (2 Peter 3, Matthew 24). For readers who hold to a global Flood, this alternative is a non-starter.

Alternative 3: "Nephilim" as a Title, Not a Bloodline

Perhaps "Nephilim" simply became a generic term for "terrifying giants," used loosely by later writers the way "Goliath" became a name for any huge opponent (e.g., 2 Samuel 21). On this reading, the spies called the Anakim "Nephilim" because they were big and scary, not because they were genealogically descended from the pre-Flood beings.

This is held by a number of careful commentators. Its strength is that it respects the difference between a narrator's authoritative statement and a terrified spy's hyperbole. Its weakness is that it still leaves the actual giant clans (Anakim, Rephaim) unexplained — where did those peoples come from, if not from the pre-Flood Nephilim?

An Honest Assessment

If you hold the supernatural view of Genesis 6 (sons of God = divine beings) and a global Flood, the second-incursion theory is the most coherent way to account for the Canaanite giants. It takes both Genesis 6 and Numbers 13 at face value and connects them through a single consistent mechanism. Its main weakness — that it is an inference rather than an explicit statement — is real, but the inference is a strong one given what the rest of the text says about spiritual rebellion and territorial powers.

If you hold a more human-scale reading of Genesis 6 (sons of God = Seth's line), the genetic-carryover or loose-title explanations will be more attractive, because you don't have a supernatural mechanism in the first place.

What is clear, regardless of which view you take, is that the Bible is not embarrassed by giants. The conquest narrative assumes they are real, the text names them by clan (Anakim, Rephaim, Emim, Zamzummim), and it traces their presence back to the original Genesis-6 corruption in some way. The question the second-incursion theory forces is whether that connection is literal recurrence, lingering genetics, regional survival, or shared reputation — and each reader will have to weigh how much strangeness the text is allowed to carry.

This article synthesizes material from the GenSix411 libraries, including the work of Michael S. Heiser and Timothy Alberino on the post-Flood giant clans. For cited detail on any passage, ask the AI or explore the related questions below.

The competing theories at a glance