'Closely' in the Bible

Then he put the tunic on Aaron, wrapped the sash around him, and clothed him with the robe. Next he put the ephod on him and placed on him the decorated band of the ephod, and fastened the ephod closely to him with the band.

You must not have sexual intercourse with both a woman and her daughter; you must not take as wife either her son's daughter or her daughter's daughter to have intercourse with them. They are closely related to her -- it is lewdness.