Must the land gifted by my father be returned, or can its construction be postponed due to a lack of financial means, knowing that the donor's condition was to build a center for memorizing the Holy Quran and a house for me?

A father must be just among his children in giving gifts. It is not permissible for him to single out one child with a gift unless it is for the purpose of upholding justice. This is based on what was narrated from Nu'man ibn Bashir, that the Prophet, peace and blessings be upon him, ordered him to retract his gift to his son because he did not treat his children equally in it, saying: "Did you give all your children the like of it?" He said, "No." He said, "Then take it back."

Therefore, if the father stipulated in the gift of the land to one of his sons that he build a Qur'an memorization center on it, there is no harm if the cost of the building is equivalent to the value of the land. However, if the value of the land exceeds the cost of the building, the father must either reclaim the excess or compensate the remaining children by the amount of that excess; otherwise, the gift would be unjust. Consequently, if the value of the land is higher than the cost of the building, and the father did not compensate the remaining children, the land must be returned to correct the transaction.