SB 2.3.17

āyur harati vai puṁsām
 udyann astaṁ ca yann asau
tasyarte yat-kṣaṇo nīta
 uttama-śloka-vārtayā
Word for word: 
āyuḥ — duration of life; harati — decreases; vai — certainly; puṁsām — of the people; udyan — rising; astam — setting; ca — also; yan — moving; asau — the sun; tasya — of one who glorifies the Lord; ṛte — except; yat — by whom; kṣaṇaḥ — time; nītaḥ — utilized; uttama-śloka — the all-good Personality of Godhead; vārtayā — in the topics of.
Translation: 
Both by rising and by setting, the sun decreases the duration of life of everyone, except one who utilizes the time by discussing topics of the all-good Personality of Godhead.
Purport: 

This verse indirectly confirms the greater importance of utilizing the human form of life to realize our lost relationship with the Supreme Lord by acceleration of devotional service. Time and tide wait for no man. So the time indicated by the sunrise and the sunset will be uselessly wasted if such time is not properly utilized for realizing identification of spiritual values. Even a fraction of the duration of life wasted cannot be compensated by any amount of gold. Human life is simply awarded to a living entity (jīva) so that he can realize his spiritual identity and his permanent source of happiness. A living being, especially the human being, is seeking happiness because happiness is the natural situation of the living entity. But he is vainly seeking happiness in the material atmosphere. A living being is constitutionally a spiritual spark of the complete whole, and his happiness can be perfectly perceived in spiritual activities. The Lord is the complete spirit whole, and His name, form, quality, pastimes, entourage and personality are all identical with Him. Once a person comes into contact with any one of the above-mentioned energies of the Lord through the proper channel of devotional service, the door to perfection is immediately opened. In the Bhagavad-gītā (2.40) the Lord has explained such contact in the following words: “Endeavors in devotional service are never baffled. Nor is there failure. A slight beginning of such activities is sufficient even to deliver a person from the great ocean of material fears.” As a highly potent drug injected intravenously acts at once on the whole body, the transcendental topics of the Lord injected through the ear by the pure devotee of the Lord can act very efficiently. Aural realization of the transcendental messages implies total realization, just as fructification of one part of a tree implies fructification of all other parts. This realization for a moment in the association of pure devotees like Śukadeva Gosvāmī prepares one’s complete life for eternity. And thus the sun fails to rob the pure devotee of his duration of life, inasmuch as he is constantly busy in the devotional service of the Lord, purifying his existence. Death is a symptom of the material infection of the eternal living being; only due to material infection is the eternal living entity subjected to the law of birth, death, old age and disease.

The materialistic way of pious activities like charity is recommended in the smṛti-śāstras as quoted by Śrīla Viśvanātha Cakravartī Ṭhākura. 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 brāhmaṇa. If the money is given in charity to a non-brāhmaṇa (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 brāhmaṇa, even then the money is returned double. If the money is given in charity to a learned and fully qualified brāhmaṇa, the money is returned a hundred and a thousand times, and if the money is given to a veda-pāraga (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-gītā (vedaiś ca sarvair aham eva vedyaḥ). 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-dhāma gatvā 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.