In the context of biblical law and ritual purity, the term "clean man" refers to an individual who is ceremonially pure and thus eligible to perform certain religious duties or assist others in purification processes. The concept of cleanliness in the Bible is deeply rooted in the Levitical laws, which outline the distinctions between what is considered clean and unclean, both in terms of physical hygiene and spiritual purity.

Biblical References:

1. Levitical Law and Ritual Purity:
The Book of Leviticus provides extensive instructions on cleanliness, particularly in chapters 11-15. These chapters detail various conditions that render a person unclean, such as contact with dead bodies, certain diseases, and bodily discharges. The "clean man" is one who has adhered to these laws and is free from such impurities.

2. Role in Purification:
In Numbers 19, the "clean man" plays a crucial role in the purification process involving the ashes of the red heifer. Numbers 19:9 states, "Then a man who is clean shall gather up the ashes of the heifer and deposit them outside the camp in a ceremonially clean place." This indicates that only a person who is ceremonially clean can handle the ashes used for purification from sin.

3. Symbolism of Cleanliness:
Cleanliness in the Bible often symbolizes holiness and separation from sin. Psalm 24:3-4 asks, "Who may ascend the hill of the LORD? Who may stand in His holy place? He who has clean hands and a pure heart, who does not lift up his soul to an idol or swear deceitfully." Here, clean hands represent moral integrity and purity of heart, essential for approaching God.

4. New Testament Perspective:
While the New Testament shifts the focus from ritual purity to spiritual purity, the concept of cleanliness remains significant. Jesus emphasizes the importance of inner purity over external rituals. In Matthew 23:25-26 , He rebukes the Pharisees, saying, "Woe to you, scribes and Pharisees, hypocrites! You clean the outside of the cup and dish, but inside they are full of greed and self-indulgence. Blind Pharisee! First clean the inside of the cup and dish, so that the outside may become clean as well."

5. Spiritual Application:
The "clean man" in a spiritual sense is one who has been cleansed by faith in Christ. 1 John 1:7 declares, "But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin." This cleansing is not merely external but involves a transformation of the heart and mind.

Theological Significance:

The concept of the "clean man" underscores the biblical theme of holiness and the necessity of purity to approach God. It highlights the distinction between the holy and the common, the pure and the impure, which is a recurring theme throughout Scripture. The laws concerning cleanliness serve as a reminder of God's holiness and the call for His people to be set apart. In the New Testament, this call to purity is fulfilled in Christ, who provides the ultimate cleansing from sin, enabling believers to stand before God as clean and holy.