‘Now the Passover of the Jews was at hand, and many went up to Jerusalem out of the country before the Passover, to purify themselves.'
Crowds were now beginning to gather in Jerusalem to prepare for the Passover. They wished to go through the seven day period of purifying there to ensure that they did not risk contact with anything (such as a dead body) which might make them not fit to play a full part in the rites. No one who was ritually unclean could partake of the Passover.