Direct discourse is the exact words of what a person said. Indirect discourse simply reports on what someone said.
Indirect discourse:
Jeb noted that if we didn’t act soon, the whole system would implode.
Direct discourse:
Jeb yelled, “If we don’t act soon, the whole system will implode.“
In English, quotation marks are used to set off direct discourse.
Greek:
οτι is often used to set off direct discourse (GGBB 454). See Machen (§306-308) for indirect discourse.
Hebrew:
The infinitive לֵּאמֹר is used to initiate direct discourse.