Full Idea
True future events cannot be such as do not possess causes on account of which they will happen; therefore that which is true must possess causes: and so, when the [true future events] happen they will have happened as a result of destiny.
Gist of Idea
The causes of future true events must exist now, so they will happen because of destiny
Source
report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 9.23-8
Book Reference
Long,A.A.: 'Hellenistic Philosophy' [Duckworth 1986], p.102
A Reaction
[exact ref unclear] Presumably the current causes are the truthmakers for the future events, and so the past is the truthmaker of the future, if you are a determinist.
Related Ideas
Idea 21389 Carneades distinguished logical from causal necessity, when talking of future events [Long on Carneades]
Idea 21390 Future events are true if one day we will say 'this event is happening now' [Carneades]