The Feast of Tabernacles originally lasted 7 days but another day, the last and greatest day, had been added making it 8 days in length. We are not told which day Jesus came to Jerusalem, but we know that He suddenly and unexpectedly appears, teaching in the temple in the middle of the Feast, in apparant fulfilment of #Mal 3:1. The Jewish leaders who were seeking Him get their wish, He is openly and publicly teaching in the most public place in the nation.

Mal 3:1  “See, I will send my messenger, who will prepare the way before me. Then suddenly the Lord you are seeking will come to his temple; the messenger of the covenant, whom you desire, will come,” says the LORD Almighty.