OT clean and unclean

The ideas of clean and unclean from the Old Testament are also used in the New Testament.

The word "clean" doesn't refer to sin. For example, it is not a sin to give birth yet that makes you unclean.

Speak unto the children of Israel, saying, If a woman have conceived seed, and born a man child: then she shall be unclean seven days; according to the days of the separation for her infirmity shall she be unclean. (Leviticus 12:2)

The word "clean" can mean wicked or evil.

And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease. (Matthew 10:1)

Similarly to the word "flesh", the word "clean" has various meanings.

Jesus makes us clean. Whatever does this mean? Apparently, in the spiritual realm, original sin contaminates our soul.

If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. (1 John 1:9)

Just as sprinkling the blood of animal sacrifices in the Old Testament cleanses the worshippers, so also, sprinkling the blood of Jesus on believers cleanses us of our sin and puts us in right standing with God.

But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin. (1 John 1:7)

Moreover he sprinkled with blood both the tabernacle, and all the vessels of the ministry. And almost all things are by the law purged with blood; and without shedding of blood is no remission. (Hebrews 9:21,22)

And he shall sprinkle of the blood upon it with his finger seven times, and cleanse it, and hallow it from the uncleanness of the children of Israel. (Leviticus 16:19)

Notice that Christians are not literally sprinkled on their physical body with the physical blood of Jesus but, rather, this occurs with the spiritual blood of Jesus on our spiritual body. Just as Abel's blood spilled on the ground, so also did the blood of Jesus.

And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel. (Hebrews 12:24)

I can imagine that in the spiritual realm there is some sort of ceremonial sprinkling of the blood of Jesus over us, to cleanse us. Usually it's thought of as all figures of speech but doing this renders it unintelligible.

I was in a meeting of Baptists once in which they were getting all excited about the blood of Jesus, but I didn't know what they were talking about because even though his blood was not physically present, they acted as if it was. Somehow Jesus took his blood and applied it to the doorpost on the Passover and the Mercy Seat in the tabernacle. This could only happen in the spiritual realm — and so it did.

The redeemed are cleansed by the blood of Jesus, the sacrificial lamb. This is an actual event occurring in the spiritual realm.

And one of the elders answered, saying unto me, What are these which are arrayed in white robes? and whence came they? And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb. (Revelation 7:13,14)

The confusion of the concepts of holiness and cleanness leads to the idea that the body is bad. In Old Testament times, getting leprosy made you unclean, but there is nothing sinful about getting leprosy. The blood of sacrifices was used to cleanse people and sacred objects.

It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these. (Hebrews 9:23)

It is not a sin to have leprosy, therefore, the word "clean" does not mean sin.

Then the priest shall consider: and, behold, if the leprosy have covered all his flesh, he shall pronounce him clean that hath the plague: it is all turned white: he is clean. (Leviticus 13:13)

When you are unclean in the eyes of God, he cannot look upon you anymore.

According to their uncleanness and according to their transgressions have I done unto them, and hid my face from them. (Ezekiel 39:24)

The religious leaders of Jesus' day were obsessed with rituals such as washing hands and cups; these practices having support from the Old Testament. Washing was a way of becoming clean with God and physical cleanliness was tangled-up with spiritual cleanliness. Jesus corrects them: that the condition of the heart is the important thing, not mere ritualistic observances. But rejecting all rituals as having no value is wrong also; Jesus doesn't suggest they change their religious lifestyle, only that they have a clean heart before God. Thus, Catholic and Orthodox ceremonies and rituals have great benefit when mingled with faith; it is wrong to reject such as these out of hand.