In this connection, Srila Bhaktisiddhanta Sarasvati Thakura quotes the following verses from Srimad-Bhagavatam (2.3.17-24):

"Both by rising and 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. Do the trees not live? Do the bellows of the blacksmith not breathe? All around us, do the beasts not eat and discharge semen? Men who are like dogs, hogs, camels and asses praise those men who never listen to the transcendental pastimes of Lord Sri Krsna, the deliverer from evils. One who has not listened to the messages about the prowess and marvelous acts of the Personality of Godhead and has not sung or chanted loudly the worthy songs about the Lord should be considered to possess ears like the holes of snakes and a tongue like that of a frog. The upper portion of the body, though crowned with a silk turban, is only a heavy burden if not bowed down before the Personality of Godhead, who can award mukti [freedom]. And the hands, though decorated with glittering bangles, are like those of a dead man if not engaged in the service of the Personality of Godhead Hari. The eyes which do not look at the symbolic representations of the Personality of Godhead Visnu [His forms, name, quality, etc.] are like those printed on the plumes of a peacock, and the legs which do not move to the holy places [where the Lord is remembered] are considered to be like tree trunks. The person who has not at any time received upon his head the dust from the feet of a pure devotee of the Lord is certainly a dead body. And the person who has never experienced the flavor of the tulasi leaves from the lotus feet of the Lord is also a dead body, although breathing. Certainly that heart is steel-framed which, in spite of one's chanting the holy name of the Lord with concentration, does not change and feel ecstasy, at which time tears fill the eyes and the hairs stand on end."