Of the three, an ongoing charity may run into obstacles, and a righteous child may pass away, but beneficial knowledge—through which Muslims continue to profit—remains for as long as Allah wills. So, my brother, be earnest in seeking knowledge, for nothing equals it, as Imam Ahmad said to the one whose intention is sound. Pursue the sacred sciences and the auxiliary fields that serve them—such as Arabic grammar and the like—until Allah benefits you and benefits others through you. Allah alone is the granter of success.