Is it permissible to postpone getting rid of usurious gains until next year to use them for marriage now, with the intention of giving out an equal amount later, due to the unavailability of an alternative like a benevolent loan?

The basic principle is the obligation to dispose of usurious gains, as they are unlawful wealth that is not permissible to benefit from. Instead, they should be spent on the welfare of Muslims or given to the poor and needy. However, if the possessor is poor and in need, they may take from it according to their necessity, and it becomes permissible for them. Therefore, it is not permissible to take from these gains except in cases of need and poverty; otherwise, it becomes a debt upon the taker until it is repaid.