"On that last day of the festival, the great day, while Jesus was standing there, he cried out, 'Let anyone who is thirsty come to me, and let the one who believes in me drink...'"
It was a major festival - the Festival of Booths. It commemorated Israel's wilderness wandering and God's provisions. This week-long celebration remembered how God provided water when they were thirsty (from the rock Moses struck with his staff)... as well as looked ahead to the "wells of salvation" (Isaiah 12:3) tat will come with the Messiah - God's chosen Savior.
To observe this dual focus, a priest would take a golden pitcher and fill it with water from the Pool of Siloam... then march it up to the Temple in Jerusalem. The people would follow him in a procession. This happened every day of the 7-day festival. So imagine the irony (or divine timing!) when Jesus shows up on day 7... possibly in the middle of the golden pitcher procession... and announces to all who'll listen that if they're THIRSTY (really thirsty!), they can come to him and drink.
It would be kind of like Jesus showing up during the half-time show at the Superbowl and announcing to the world that if anyone wants to be a "true champion" they should come to him. Or if he'd pop up in Hollywood at the Oscars and declare to the star-studded audience that it's only in His presence where one can be a "real winner." (Theologically, you may take issue with these analogies, but socially & culturally, I think it's right on the mark!)
Jesus was such a great teacher, he used whatever context he was in to help people see the deeper truths of God. Wherever he went, people were astonished at his teachings. How awesome that we, too, can "hear" his wisdom through the pages of Scripture. May I forever drink deeply from this wellspring of life! AMEN.