John Chrysostom — as excerpted in the Catena Aurea on John 7:37-39

“Which lasted seven days. The first and last days were the most important; In the last day, that great day of the feast, says the Evangelist. Those between were given chiefly to amusements. He did not then make the offer on the first day, or the second, or the third, lest amidst the excitements that were going on, people should let it slip from their minds, He cried out, on account of the great multitude of people present.”