Abu Huraira (may Allah be pleased with him) narrates that the Prophet (peace and blessings of Allah be upon him) said: "Indeed, everything has a period of enthusiasm and vigor, and for every period of enthusiasm and vigor there is also a period of weakness and laziness. If the one who is enthusiastic maintains moderation and avoids excess, then hope for his (success), and if fingers are pointed towards him (he becomes famous), then do not count him." Hasan, narrated by Tirmidhi.