After Jesus rose from the dead, he reminded his disciples how he had told them, “Everything must be fulfilled that is written about me in the Law of Moses, the Prophets and the Psalms” (Luke 24:44). Psalm 69:21 specifically foreshadows how Jesus would receive gall and vinegar at his crucifixion. First he was offered wine mixed with gall, which was to help alleviate pain. Jesus rejected the painkiller (see Matthew 27:32–34), choosing instead to drink the full cup of suffering his Father had given him (see John 18:11). Later, just before he died, Jesus cried out in thirst and was given wine vinegar to drink (see John 19:28–30).
Jesus was well aware of the Messianic prophecies, and he fulfilled each one—even one as specific as this one—involving gall and vinegar—buried here in the Psalms.