Certain commands in Torah relating to uncleanness appear cumbersome, inconvenient, and obsolete today, yet this concept of uncleanness is repeated in the New Testament as if it were eternally relevant. (Ep 5:3) As with many of God’s laws, the benefits of observing them are not easily understood.
As an example, laws regarding menstruation require a woman on her period be put apart for a week. (Le 15:19) If this is a quarantine, requiring the woman to be physically isolated and left alone whenever she’s on her monthly cycle, this may seem cruel, unnecessary, and terribly inconvenient for both the woman and the rest of her family.
However, the Hebrew word for apart is נדּה (niddâh), the same word for the menstrual fluid (Le 19:24), so the word itself evidently doesn’t require the woman be physically separated from others, simply identified as being on her period: set apart from others in this sense. This is actually helpful to the woman; others in the family understand she’s under additional physical and emotional stress and give her additional space and mercy.
Additionally, the law specifies that everything the woman sits or lies on during this time becomes unclean, tainted or polluted, and that anyone touching these objects must bathe and wash their clothes and is unclean the rest of the day.
Without access to recent advancements in feminine hygiene, from what we know scientifically, this practice of actually separating objects potentially contaminated with menstrual discharge seems very healthy for preventing disease, and providing a separate physical space for the woman during this time certainly helps contain the uncleanness.
Yet even with advanced hygiene it’s not generally an imposition for all in the home to bathe and/or shower daily and to wash the bedsheets and clothes as the cycle ends. Nothing here is terribly onerous, needlessly inconvenient or necessarily troublesome.
Toward the end of the immediate context, comprising similar laws relating to bodily discharges, we see the ultimate and primary application: when we’re interacting with the physical presence of God in the earthly temple, this kind of uncleanness can be lethal. (Le 15:31)
We may infer from this what we will, but the implication seems to be that we all become unacceptably unclean in just living life in this filthy world and are in constant need of purification. To followers of Christ, this is no surprise: we’re in continual need of cleansing and forgiveness. (1Jn 1:8-9) Perhaps these kinds of laws are given partly as a cyclical physical reminder of God’s holiness (Is 64:6) and of our innate uncleanness apart from Him. (Is 6:5)
Apart from the earthly temple, the impact of uncleanness evidently vanishes in the ceremonial context; what remains is simply physical hygiene, the spiritual lessons we might infer from this, and respecting God’s commands as well as we can because we love Him and delight in His laws. (Ro 7:22)
Becoming ceremonially unclean isn’t sinful; after all, the human body is simply functioning according to God’s perfect design. What is sinful is neglecting to take appropriate steps to manage the uncleanness and limit its impact in our family and community, thereby promoting unnecessary uncleanness and exposing others to harm. (Ep 5:5) This violates the law of Love. (Ro 13:10)
All of God’s laws are faithful (Ps 119:86), truth (151), and righteousness (172); in keeping them as intended there is great reward. (Ps 19:11)