I'm currently reading through Leviticus. Here's what I've gathered so far:

  • Leviticus 5:2: Certain livestock animals were considered unclean.
  • Leviticus 5:3: Actions such as touching a dead body made a person unclean.
  • Leviticus 10:10: This verse is about the importance of distinguishing between the holy and unholy, and between the clean and the unclean.
  • Leviticus 11: Certain foods, including pork, certain fish, and certain birds, were considered unclean and forbidden.
  • Leviticus 13:3: Skin infections could render a person unclean.

3 The priest shall examine the sore on the skin of the body; and if the hair on the sore has turned white, and the sore appears to be deeper than the skin of his body, it is a leprous sore. Then the priest shall examine him, and pronounce him unclean.

These verses all speak of being unclean, but none of them define a specific meaning. I'm seeking to understand the overarching concept of being "unclean".

So my question is: What does it mean to be "unclean"?

4 Answers 4


The concept of being unclean was originally concerned with preserving the holiness of the sanctuary or temple - and by extension, the people attending it. Thus, while there was no penalty for becoming ritually "unclean," to enter the temple in a state of impurity was a serious offense. In the case of corpse defilement, for example, it was theoretically punishable by being expelled from the congregation of the Israelites:

Numbers 19:20

Those who become unclean and fail to purify themselves—those people will be cut off from the assembly, because they defile the sanctuary of the Lord.

The OP's list of examples of "uncleanness" is far from complete. But please note two facts: becoming unclean was not a moral sin. It many cases it was unavoidable, such as the case of menstruation, sex between a married couple or dressing a dead body. With regard to eating unclean animals, the Law's concern was not with the animals per se but with the fact that touching/eating them rendered the person ritually impure. Thus the text routinely emphasizes the effects of these animals on humans, rather than condemning the animals themselves, who are creations of God.

Leviticus 11:8

You shall not eat their meat, and you shall not touch their carcasses; they are unclean for you.

Conclusion: While there are various meanings of "being unclean," the key point of this designation was to protect holiness of God's sanctuary. In that sense, being unclean means to be unqualified to enter the tabernacle or temple. In some cases, it was "contagious" (e.g. - a person became unclean by touching a person with a skin disease or a menstruating woman conferred). After the Israelites settled in Canaan and later lived in the diaspora, ritual purity became less focused on the sanctuary and more central to daily life as a Jew.


The fundamental distinction between "clean" and "unclean" is used almost synonymously with the concept of "holy" vs "unholy" and is related to the basic foundation on which the nation of Israel rested as stated in the pre-amble to the Israelite covenant:

Ex 19:5, 6 - Now if you will indeed obey My voice and keep My covenant, you will be My treasured possession out of all the nations—for the whole earth is Mine. And unto Me you shall be a kingdom of priests and a holy nation.’ These are the words that you are to speak to the Israelites.”

Thus, anything "unclean" rendered the person "unholy" which meant one of two things:

  • exclusion from the holy camp of Israel until "cleanness" was restored, or
  • permanent expulsion from Israel

Note the following:

  • Lev 10:10 - You must distinguish between the holy and the common, between the clean and the unclean
  • Lev 22:4 - If a descendant of Aaron has a skin disease or a discharge, he may not eat the holy offerings until he is clean. (see also V7)
  • Isa 66:20 - And they will bring all your brothers from all the nations as a gift to the LORD on horses and chariots and wagons, on mules and camels, to My holy mountain Jerusalem,” says the LORD, “just as the Israelites bring an offering in a clean vessel to the house of the LORD.”
  • Eze 22:26 - Her priests do violence to My law and profane My holy things. They make no distinction between the holy and the common, and they fail to distinguish between the clean and the unclean. They disregard My Sabbaths, so that I am profaned among them.
  • Eze 44:23 - They are to teach My people the difference between the holy and the common, and show them how to discern between the clean and the unclean.

This persisted into the NT where we read:

  • Acts 10:14 - But Peter said, "In no way, Lord! For never have I eaten anything common/unholy or unclean." See also V28 and 11:8.

The basis for the new covenant, elaborated in the 1 Peter 1 & 2 is the same as the Israelite covenant (as quoted)

1 Peter 2:9 - But you are a chosen people, a royal priesthood, a holy nation, a people for God’s own possession, to proclaim the virtues of Him who called you out of darkness into His marvelous light.

See also APPENDIX below.

Now, many of the requirements in Leviticus we would now recognize as simply good hygiene and good health practices. However, in ancient Israel, this was simply stated as "clean" vs "unclean".

APPENDIX - New Covenant

One of the best summaries of the New Covenant is found in 1 Peter 1, 2.

  • It is based on the Law of Love. Though you have not seen Him, you love Him; and though you do not see Him now, you believe in Him and rejoice with an inexpressible and glorious joy, now that you are receiving the goal of your faith, the salvation of your souls. (1 Peter 1:8, 9); Since you have purified your souls by obedience to the truth so that you have a genuine love for your brothers, love one another deeply, from a pure heart. (1 Peter 1:22); Honour everyone: love the brotherhood, fear God, Honour the king. (1 Peter 2:17).
  • Purpose: “But you are a chosen people, a royal priesthood, a holy nation, God’s special possession, that you may express the praises of him who called you out of darkness into his wonderful light … Live such good lives among the pagans that, though they accuse you of doing wrong, they may see your good deeds and glorify God on the day he visits us.” 1 Peter 2:9, 12. (See also Matt 5:16.)
  • The promise: Salvation by grace through the promised Messiah, 1 Peter 1:3-12, 20, and freedom from slavery to sin, 1 Peter 2:16. (See also 2 Peter 2:19.)
  • Moral Requirements: holiness (1 Peter 1:15), Purity (v22), Obey the truth (v22), love (v22), “rid yourselves of all malice and all deceit, hypocrisy, envy, and slander of every kind” (1 Peter 2:1), abstain from sinful desires (1 Peter 2:11), submit to civil authorities (v13-17), see also Rom 13:1-7, etc.
  • Sacrifice: Blood of Jesus, 1 Peter 1:18, 19, with its “sprinkled blood of the new covenant” of “Grace and peace” as per V2.

It’s hard to narrow “unclean” down to a specific rule. Tim Mackie suggests that it’s anything that has to do with the boundary between life and death (birth fluid, sex fluid, dead animals, skin disease). But this doesn’t explain unclean animals. (although animals like crows and vultures are unclean possibly because they eat dead animals)

I would suggest it is anything that is outside its perceived order. When God created the world he separated everything into its correct order. Land creatures, sea creatures, day, night, etc.

Things that are unclean are things that have crossed outside their correct order. A sky creature that walks on the land. A sea creature that walks on dry land.

Menstruation: blood belongs on the inside. Childbirth: birth fluid and pain are out of place. Skin disease: perhaps pussy scabs have crossed the skin barrier. Death: death is seen as outside God’s good intended ordered creation of Life.

It’s not a completely satisfactory answer I know, but i think that way of viewing the world and creation is closer to the ancient worldview.

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    Commented Mar 23 at 2:41

Clean and unclean are first mentioned in Genesis 7 and 8. From Genesis 7:2, it seems that God explained to Noah the difference between clean and unclean animals to take on the ark. Note that this is before God changed the vegetarianism of humanity in Genesis 1:30 to allow a carnivore diet in Genesis 9:3 without restriction to clean and unclean animals.

This would lead me to conclude that the difference between clean and unclean animals pertained only to sacrifices made to God at that time as indicated in Genesis 4:4 and Genesis 8:20.

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