Reference for Leviticus 15:28

וְאִֽם־טָהֲרָ֖ה מִזּוֹבָ֑הּ וְסָ֥פְרָה לָּ֛הּ שִׁבְעַ֥ת יָמִ֖ים וְאַחַ֥ר תִּטְהָֽר׃

But if she be cleansed of her issue, then she shall number to herself seven days, and after that she shall be clean.