the outward sense of the ḥadīth is that it conveys an outright prohibition.
If the husband has actually carried out the khulʿ so that the marriage bond has been dissolved and only the transfer of the compensation remains, he no longer has any right of withdrawal, even if he has not yet received that compensation.
But if they have merely spoken about it without effecting the dissolution—agreeing only that he will dissolve the marriage once she pays the compensation—no dissolution has yet taken place; what exists is merely a promise, and he is free to retract from an intention he has not yet acted upon.
Thirdly, Sayyid Quṭb remarks: “The combined reports concerning the case of Thābit ibn Qays and his wife depict the psychological state the Messenger of Allah ﷺ encountered. He dealt with it as one who realizes that it was a coercive situation in which condemning it or forcing the woman to remain with her husband would be futile. Instead, he chose for her a solution drawn from the divine methodology—one that addresses human nature in a candid, practical, and realistic way, and treats the human soul with full awareness of the genuine emotions that surge within it.”