What is the ruling on saving in a usurious bank, both in the past and in the present, and what is the ruling on the lifelong salary obtained therefrom? Is it permissible to use it for medical treatment, building a house, or purchasing a plot of land?

It is not permissible to deposit money in usurious banks or to deal with them except in cases of extreme necessity, due to the availability of Islamic alternatives. The prizes offered by usurious banks, such as granting a lifelong salary, are a trick to transform usurious interest into prizes distributed by lottery. This combines usury (riba) and gambling (maysir (definition)). These prizes are forbidden, and whoever receives anything from them must dispose of it by spending it on charitable causes and for the benefit of Muslims, or by giving it to the poor and needy. It is not permissible for him to benefit from it unless he is poor and in need, in which case he may take only what he needs.