Al-Shāfiʾī, may Allah be pleased with him, said: “I accompanied the Sufis and I only benefited from two of their sayings. First, ‘Time is a sword; if you do not slay it, it will slay you.’ And the second: ‘Keep your soul occupied with good, otherwise it will keep you occupied with evil.'”
One’s time is in fact one’s life, and the substance of one’s eternal life in lasting pleasure or of a life of suffering in severe torment. It passes faster than the passing of clouds, and the portion of one’s time that was for Allah and with Allah is part of one’s life, while the rest is not counted as part of one’s life even if one lived long, for one was living the life of animals. For the one who spends his time in negligence, desires and false wishes, and spends most of his time in sleeping and idleness, then the death of such a person is better for him than his life. And if one has of one’s prayer only that part in which one was conscious, as in the hadith, then similarly what counts of one’s life for one is only that which was spent for Allah and with Allah.
[The Value of Time, Shaykh ‘Abd Al-Fattāḥ Abū Ghuddah, pg. 8]