The materialistic way of pious activities like charity is recommended in the smrti-sastras as quoted by Srila Visvanatha Cakravarti Thakura. Money given in charity to a suitable person is guaranteed bank balance in the next life. Such charity is recommended to be given to a brahmana. If the money is given in charity to a non-brahmana (without brahminical qualification) the money is returned in the next life in the same proportion. If it is given in charity to a half-educated brahmana, even then the money is returned double. If the money is given in charity to a learned and fully qualified brahmana, the money is returned a hundred and a thousand times, and if the money is given to a veda-paraga (one who has factually realized the path of the Vedas), it is returned by unlimited multiplication. The ultimate end of Vedic knowledge is a realization of the Personality of Godhead, Lord Krishna, as stated in the Bhagavad-gita (vedais ca sarvair aham eva vedyah). There is a guarantee of money’s being returned if given in charity, regardless of the proportion. Similarly, a moment passed in the association of a pure devotee by hearing and chanting the transcendental messages of the Lord is a perfect guarantee for eternal life, for returning home, back to Godhead. Mad-dhama gatva punar janma na vidyate. In other words, a devotee of the Lord is guaranteed eternal life. A devotee’s old age or disease in the present life is but an impetus to such guaranteed eternal life.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Second Canto, Chapter 3 – Text 17