Vita brevis & mutabilis. Marcus Aurelius 5.23

Are things bad, for you or the world? Take comfort: nothing lasts forever, and human affairs are known to change dramatically overnight.

Πολλάκις ἐνθυμοῦ τὸ τάχος τῆς παραφορᾶς καὶ ὑπεξαγωγῆς τῶν ὄντων τε καὶ γινομένων. ἥ τε γὰρ οὐσία οἷον ποταμὸς ἐν διηνεκεῖ ῥύσει καὶ αἱ ἐνέργειαι ἐν συνεχέσι μεταβολαῖς καὶ τὰ αἴτια ἐν μυρίαις τροπαῖς καὶ σχεδὸν οὐδὲν ἑστὼς καὶ τὸ πάρεγγυς· τὸ δὲ ἄπειρον τοῦ τε παρῳχηκότος καὶ μέλλοντος ἀχανές, ᾧ πάντα ἐναφανίζεται. πῶς οὖν οὐ μωρὸς ὁ ἐν τούτοις φυσώμενος ἢ σπώμενος ἢ σχετλιάζων ὡς ἔν τινι χρονίῳ καὶ ἐπὶ μακρὸν ἐνοχλήσαντι;

Take time often to ponder how swiftly things that exist must pass away, how soon things that are currently building must vanish. For this realm of being goes by like a river in constant flood. Its works are evolving continuously, and its causes drive off in so many changing directions that hardly anything remains fixed, including whatever is close to us. Its infinite abyss holds what is gone and what is yet to come, gaping wide as all things disappear into it. In these circumstances, how could anyone but a fool boast, or blame himself, or complain, as though his brief moment of life were more than a fleeting burden?