What is the ruling on saying: "O the wretchedness of fate"? And does it involve reviling time?

This phrase is directed at one's lot (luck), not at time. "Sakhf" (سخف) means lightness and delicacy. Describing one's lot as "sakhf" could carry two meanings: either describing it as little and weak, like saying: "Oh, how little provision and how weak the situation!" or describing it as light and foolish, like saying: "Oh, how foolish the decrees!" The first meaning is permissible, but the second is considered an aspersion on God's wisdom and management, and there is a fear of apostasy for its speaker, so he must repent. A Muslim must avoid such ambiguous expressions that could imply both truth and falsehood.