Cleanliness is next to godliness. That saying reflects what is discussed in Leviticus 11. This chapter lists things that are unclean and ways people become unclean. This uncleanness is a ceremonial uncleanness, but it reflects the holiness of God. Verses 44 and 45 include admonitions to be holy as God is holy.
For I am the Lord your God. Consecrate yourselves therefore,
and be holy, for I am holy.
. . . thus you shall be holy, for I am holy.
To be holy, in part, is to be separate from that which would make us unclean. To be holy requires that we make clear distinctions between that which is of God and that which isn’t. There is no gray area with God. The only way to understand what is of God is to fill our minds and hearts with God’s Word.
How can a young man keep his way pure?
By keeping it according to Your word.
1With all my heart I have sought You;
Do not let me wander from Your commandments.
Your word I have treasured in my heart,
That I may not sin against You.