Posted by: BibleScienceGuy | July 5, 2017

Science in the Bible – Circumcision

(2 Minute Read)

Four thousand years ago, Yahweh told Abraham to circumcise males on the eighth day:
This is My covenant, which you shall keep, between Me and you and your descendants after you: every male among you shall be circumcised. And you shall be circumcised in the flesh of your foreskin, and it shall be the sign of the covenant between Me and you. And every male among you who is eight days old shall be circumcised throughout your generations, a servant who is born in the house or who is bought with money from any foreigner, who is not of your descendants. (Genesis 17:10-12 NASB)

Abraham followed this prescription with his son Isaac:
Then Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. (Genesis 21:4 NASB; cf. Acts 7:8)

Why did Yahweh order circumcision on the eighth day for Abraham’s male descendants? Why not sooner or later? Why did it have to be on Day Eight?

Some 600 years later Yahweh gave Moses the same instruction for the Israelites:
On the eighth day the flesh of his foreskin shall be circumcised. (Leviticus 12:3 NASB)

Again, why the eighth day?

The Jews, with some lapses, continued the practice of circumcision throughout their history. John the Baptist (Luke 1:57-60) and the Apostle Paul (Philippians 3:4-5) were both circumcised on the eighth day.

Even Jesus Himself was circumcised on the eighth day:
And at the end of eight days, when he was circumcised, he was called Jesus, the name given by the angel before he was conceived in the womb. (Luke 2:21 ESV)

Circumcision of Jesus
Giovanni Bellini, c. 1500

So what’s the big deal about the eighth day for circumcision?

In the 1930s, Danish scientist Henrik Dam and American scientist Edward Doisy discovered that vitamin K was necessary for blood to clot. They shared the 1943 Nobel Prize in Medicine for this research. The exact function of vitamin K, however, was not discovered until 1974.

The human body needs vitamin K to synthesize certain proteins that are required for blood clotting. Without vitamin K, uncontrolled bleeding occurs in surgical procedures like circumcision, because clotting is severely impaired.

If vitamin K is not present when a baby boy is circumcised, the baby will bleed to death. The reason Yahweh prescribed Day Eight for circumcision is that vitamin K peaks in a newborn at eight days of age. The eighth day is the optimum day for circumcision because of the maximum presence of the clotting factor vitamin K.

Today when baby boys are circumcised within a few days of birth, they are given vitamin K to facilitate blood clotting.

How did Abraham and Moses know to circumcise on the eighth day? Only the Creator, who knows every intricate detail of human physiology (because He made it), could have revealed this to them.

Science Catches Up to the Bible

Thousands of years before man discovered that vitamin K is needed for blood clotting, the Bible instructed the Jews to circumcise on the eighth day because vitamin K peaks in a newborn on this day. Only the Creator could have revealed this to the Jews.

Although the Bible is not primarily a science textbook, it does hint at many scientific truths like this one and like those mentioned in this Science in the Bible series, truths that long pre-date their discovery by today’s scientists. This is strong evidence of divine authorship of the Bible.

Questions to Ponder

1. Why would God create a body part and then command that it be removed?
2. In Galatians 5:6, what does Paul say is more important than circumcision?

Share your thoughts on these questions in the comments below. It could encourage or help another reader.

Soli Deo Gloria.

This is the 17th in the Science in the Bible series of blog posts. While there is much science connected with Creation and Noah’s Flood, this series will focus on lesser known scientific truths that were alluded to in the Bible long before they were known to scientists.
Read the prequels:
1. Science in the Bible – Blood
2. Science in the Bible – Ocean Currents
3. Science in the Bible – Undersea Mountains
4. Science in the Bible – Ocean Reservoirs
5. Science in the Bible – Good Medicine
6. Science in the Bible – Round Earth
7. Science in the Bible – Don’t Marry Kin
8. Science in the Bible – Fearfully and Wonderfully Made
9. Science in the Bible – Hanging Earth
10. Science in the Bible – Thermodynamics
11. Science in the Bible – Water Cycle
12. Science in the Bible – Quarantine
13. Science in the Bible – Starry Host
14. Science in the Bible – Turning Earth
15. Science in the Bible – Hygiene
16. Science in the Bible – Seed of Life

Read the sequel:
18. Science in the Bible – Expanding Universe

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©William T. Pelletier, Ph.D.
“contending earnestly for the faith”
“destroying speculations against the knowledge of God”
“for the defense of the gospel”
(Jude 1:3; 2 Cor 10:5; Phil 1:16)
Wednesday July 5, 2017 A.D.

Thy word is a lamp to my feet and a light to my path. (Psalm 119:105)


  1. Thank you for your hard work. These articles are excellent. Stay blessed, Mike


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