Is it permissible for a husband to ask his wife not to marry after his death so that they may be together in Paradise, and is there a precedent for this among the Companions or concerning the wives of the Prophet, peace and blessings be upon him?

First: It is not legislated for the husband to ask his wife not to marry after him, nor is it permissible for him to stipulate this to her. If he asks or stipulates it, she is not obligated to comply, especially if she is young, due to the harm involved and its contradiction to the purposes of the Lawgiver. Sheikh Ibn Uthaymeen emphasized that this condition is invalid because it contradicts the Sharia.

Second: The preponderant opinion is that a woman in Paradise will be with her last husband in this world, according to what is stated in the Hadith. However, this does not mean the legality of a will not to marry after the death of the other spouse, and this was not known among the Salaf. Rather, they used to marry after the death of their spouses. If the spouses agree and the wife desires not to marry after him in order to reunite with him in Paradise, there is no harm in that for her, but it is not recommended or stipulated.

Third: Allah prohibited the marriage of the Prophet's wives (peace be upon him) after him, because they are the Mothers of the Believers and his wives in this world and the Hereafter, as stated in the noble verse, and scholars have unanimously agreed upon this.