One final point connected to last week’s Parsha. We learn an important Halachic concept from the Pasuk וספרה לה שבעת ימים, that she counts for herself seven days. The Rabbis learn from this עד אחד נאמן באיסורים, that one witness is believed in matters of איסורים.
This means that we trust the testimony of one person regarding whether something is permitted or forbidden. For example, one individual is trusted to let us know how much milk fell into a meat dish. This way we figure out if it is אסור or מותר.
The section of Shulchan Aruch that deals with איסור והיתר is called יורה דעה. The main subject are things that are permitted or forbidden.
When the Torah says that two witnesses are required in a matter, this refers to cases where an actual sin was seen by two who report it to בית דין and the appropriate punishment is given.
In the first instance, we get the facts based on the testimony of one. But punishment is only meted out when there are two witnesses.