Marriage by Shighar: Its Definition and Ruling

Please tell us in detail about marriage by shighar, as there are many relatives and friends where each one is married to the other’s sister, and vice versa?
Answer: Shighar is what is done by condition: “Marry me and I will marry you.” This is shighar. If he says, “Marry me and I will marry you; I will not marry you until you marry me,” this is shighar, which is not permissible. The marriage is invalid and not permissible. However, if he proposes to him, and he proposes to him without any condition, there is no harm. He marries his sister, and he marries his sister, or his daughter, or his daughter, or his aunt, or his aunt; there is no harm, but without any condition. As for saying, “You must marry me and I will marry you; if you do not marry me, I will not marry you,” this is called marriage by shighar, and the Messenger (peace and blessings be upon him) forbade it. Yes.
The presenter: May Allah reward you with good and do you good.