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 realization of the Personality of Godhead, Lord Kṛṣṇa, 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