Is it permissible for a man married to two wives to establish a family waqf solely for his children from the first wife, without establishing a waqf for either of his wives or for the second wife who has not borne him children?

It is permissible to allocate a waqf (endowment) to sons to the exclusion of wives. For the waqf to be effective, it is a condition that the endower makes it immediate and does not suspend it until his death; otherwise, it would be considered a will, which is not permissible for an heir.

It is valid for the endower to retain supervision of the waqf for himself, according to the majority of scholars, and this is the most preponderant opinion. The Malikis disagreed, stipulating that the waqf must pass out of the endower's possession. The evidence for the majority view is what Ibn Qudamah and Ibn al-Qayyim stated: that Umar (may Allah be pleased with him) and other Companions and Rightly Guided Caliphs managed their own charitable endowments.