Is it permissible for a representative of a Mujahideen group, who collects money and receives funds that are not specified for the entity he works for, to give these funds to a second group, claiming that they are from the first group for the sake of reconciling hearts (lying for reconciliation), while committing that the money will be for the Mujahideen as it was specified when named for the entity?

The default is that lying is forbidden and must be avoided, unless there is a legitimate, recognized Shariah interest that necessitates it, as Imam An-Nawawi stated in "Riyadh As-Salihin". He mentioned that speech is a means to achieve objectives, so if a commendable objective cannot be achieved except through lying, then it is permissible. If the objective is obligatory, then lying becomes obligatory. The preferred approach is "Tawriyah," which means that the speaker intends a true meaning with his words, even if they appear to be false on the surface. Scholars have cited the Hadith of Umm Kulthum (may Allah be pleased with her), which permits lying in three situations: war, reconciling people, and a man speaking to his wife or a woman speaking to her husband. Accordingly, in the case of reconciling people, lying is permissible, provided that the donor has not specified a particular category for the donation; otherwise, it is not permissible to spend it on anything else.