Albert Barnes Commentary John 5:1

"After these things there was a feast of the Jews; and Jesus went up to Jerusalem." — John 5:1 (ASV)

A feast. Probably the Passover, though it is not certain. There were two other feasts—the Pentecost and the Feast of Tabernacles—at which all the males were required to be present, and it might have been one of them. It is of no consequence, however, which of them is intended.