2 Samuel 15:16

And Ahithophel said to Absalom, “Go in to your father’s concubines, whom he has left to keep the house; then all Israel will hear that you have made yourself odious to your father. The hands of all who are with you will also be strengthened.”

So they pitched a tent for Absalom on the roof, and Absalom went in to his father’s concubines in the sight of all Israel.

Then David came to his house at Jerusalem, and the king took the ten women, the concubines whom he had left to keep the house, and placed them under guard and provided them with sustenance, but did not go in to them. So they were shut up until the day of their death, living as widows.