How circumcision shows God exists

Have you ever wondered why God commanded the Israelites to circumcise their male children on the eighth day in the Bible? A few years back, I had the privilege of sitting in on a radio discussion with Bible teacher, Chris Hill on Yeshua Explored. During the show he made this fascinating statement:

'The ideal time to circumcise a child is the eighth day. Any earlier than that is not appropriate because vitamin k, or prothrombin as doctors call it is fully developed by the eighth day, so that is the ideal time to circumcise a child to stop him bleeding to death. How did Moses know that? Trial and error? Probably not. He didn't slaughter hundreds of kids in order to find that out. This was revelation from the Lord!'

It made me wonder. How did a culture that was ignorant of modern medicine know about the eighth day for circumcision? It seemed highly implausible that they could have discovered this for themselves. So what does this mean? Could it be incontrovertible evidence supporting the truth of the Bible? And what about the skeptics out there? Do they even have a plausible explanation? I decided to do a little digging.

My research led me down some interesting trails. I even ended up on an atheist forum where I had a very heated discussion. But before I get onto that, let's begin with the findings. Here is a detailed account of the evidence and arguments supporting the claim that Biblical circumcision supports divine inspiration.

1. The ideal time to circumcise a child is the eighth day because prothrombin is fully developed

In the Old Testament, God gave circumcision as a sign of His original covenant with the father of the Jewish nation, Abraham (Gen 7:9-11). We read of His instructions to the Jewish people in the book of Leviticus.

‘And on the eighth day the flesh of his foreskin shall be circumcised.’ Leviticus 12:3

Hermann Adolf Alexander Schmidt (1831 – April 22, 1894)

Thousands of years later in 1872, Alexander Schmidt was credited for his research with blood clotting. He was the man responsible for naming the enzyme prothrombin. In the 20th century, it was discovered that Vitamin K coupled with prothrombin, causes blood clotting or coagulation. 

According to the American Pregnancy Association the Jewish circumcision procedure is "usually performed on or shortly after the 8th day from birth when clotting factors in the babies blood are at their highest levels."

The award-winning Giving Birth Naturally also supports the case. "Newborn levels of vitamin K peak on the 8th day... If you choose to circumcise before the 8th day, it is well advised to administer vitamin K to prevent bleeding complications from the surgery."

An article shared by famous surgeon and New York Times bestseller, Dr Joseph Mercola also states:

‘Day 8 is said to be the only time in a baby's life when his prothrombin level will naturally exceed 100 percent of normal.’

I was surprised to discover that the article even goes on to mention the Bible’s very first mention of circumcision in Genesis.

‘As it turns out, Genesis 17:12 of the Bible mandates the circumcision of infant boys on the eighth day after birth—a recommendation pronounced long before we had the science to back it up.’

Here is the passage being referred to:

‘And he that is eight days old shall be circumcised among you, every man child in your generations, he that is born in the house, or bought with money of any stranger, which is not of thy seed.’ Genesis 17:12 

Dr Mercola concludes, ‘I will leave any conclusions to you about the significance of this anecdote, but it is nevertheless interesting.’

Whatever you conclude about the findings, the fact remains that Chris was absolutely right. It is a medical fact that a newborn’s natural prothrombin level peaks around the eighth day of life; the exact day that God commanded the Israelites to circumcise the male children.

2. Moses didn’t discover this by “trial and error” because he would have had to slaughter countless Israelite children in order to find that out

I found this to be a very persuasive point. World famous atheist, Richard Dawkins, accuses the God of the Old Testament of being an ethnic cleanser. Can we really be expected to believe that Israel would endanger their own bloodline by wiping out hundreds, if not thousands of their own children? And for what? To find out how soon they could cut their foreskin off without killing them? What would be the point of that? Why would they even pursue this if their newborns were constantly bleeding to death?  

Moreover, as we’ve just seen, this can actually be traced even further back to Abraham. God originally commanded him to circumcise all the male children in his house. Abraham had two sons, Isaac and Ishmael. So if Abraham made this up, he would have only had two babies, not hundreds or thousands to slaughter through trial and error! The odds seem stacked in favour of divine revelation.



The early Jews who performed circumcision's were not surgeons with modern medical knowledge. This was 4,000 years ago. There were no hospitals who could offer general anesthetic, vitamin k shots or blood transfusions. If there was haemorrhaging the babies would simply bleed to death. This was a pre-scientific age with no modern medical equipment. Even more supporting evidence showing that the eighth day command came straight from God.


What about the skeptics?

I was interested to see how the skeptics would respond to the argument and the research. It can certainly be a lion’s den on these atheist forums, but in the end I was more persuaded than ever that Biblical circumcision is a very powerful argument supporting the truth of The Bible.

Here’s a couple of actual challenges taken from an atheist Facebook group discussion. My rebuttals are presented below:

Skeptic: 'There were many different cultures before The Jews started doing circumcision. They mostly ripped it off from others. The Bible isn't evidence of your claim at all.'

My Response: According to Wikipedia, anthropologists don't even know for sure when circumcision started. Allegedly the earliest evidence comes from the Egyptians and they practiced “adult” circumcision. This verse in question is significant because it’s talking about “child” circumcision.

Can we really be expected to believe that Israel would endanger their own bloodline by wiping out hundreds, if not thousands of their own children?

While male circumcision exists in other cultures, only the Israelite culture got it spot on in terms of the ideal moment to circumcise. Ancient African circumcision for example varies greatly from the Jewish practice. It would usually occur in young warrior initiation schools or as a rite of passage from childhood to adulthood, requiring a display of courage under the knife. In South Africa it is performed most of the time on teenage boys or 18 years and older. There is no evidence however, of eighth day circumcision pre-dating The Bible. This shows this wasn't simply a result of trial and error. Otherwise you would expect to see these other ancient cultures getting to the same result.


S.I. McMillen, M.D., in his book None of These Diseases (2000) confirms that pain caused by circumcising later in life can last for up to a week. Newborns, on the other hand, are extremely resilient. So the most humane time is to circumcise in the first month of life. He also confirms that prothrombin only jumps to 110% of the adult level on the eighth day. Thus the safest day for circumcision in a baby's life is day eight.

The fact that the Bible records the exact and earliest "cut off" point for a newborn reveals a divine fingerprint. God knew exactly what he was doing. 

Skeptic: How did you come to the conclusion that an omnipotent god beamed secret knowledge into one man's brain is a more plausible explanation than people observed that babies who were circumcised too early bled to death, whereas babies who were circumcised later did not?

My Response: This is a straw man. God didn’t beam secret knowledge into Abraham or Moses’ brain. All the passage says is that He instructed them to circumcise their male children on the eighth day. Why not later when they were 10, 20 or even 30 days old? Was it purely coincidental? Is that even plausible, given the evidence?

God knows about human anatomy because He is the Creator. The Israelite's were ignorant of modern science and biology. They didn’t know about prothrombin peaking on the eighth day because it wasn’t discovered until thousands of years later. But God knew, and that’s the point. This had to be revelation from the Lord!

So what do you think? Is this a “clean cut” case? Share your comments below!

Adam James Brennan is a Digital Producer at Premier


American Pregnancy confirms 8th day levels

Giving Birth Naturally - Male Circumcision

Chris Hill on Yeshua Explored

Dr Mercola Article

History of male circumcision

Circumcision in Africa

Holt, L.E. and R. McIntosh (1953), Holt Pediatrics

Biblical Accuracy and Circumcision on the 8th Day

Alexander Schmidt (physiologist)

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