It is further clear from the poskim (halachic decisors) that the Sages’ enactment that a person may not spend more than a fifth, applies only to giving charity to the poor, but for the sake of supporting Torah study one may give even more than this amount. The reason for this is that since through this gift the person acquires the reward of the Torah study he enabled — like the tribe of Zevulun supported the tribe of Yissachar so that they could devote themselves to Torah study and Zevulun received a share of Yissachar’s Torah — therefore it is not relevant to limit how much merit one can gain from supporting Torah study, for the more one gives the more of a portion he has in that study.
