The next day the great crowd that had come for the Feast heard that Jesus was on his way to Jerusalem.
The account of the triumphal entry is given in all four gospels, thus indicating its importance (Matt 21:1-11, Mark 11:1-11, Luke 19:29-44). This happened on the Sunday preceding the Passover.
The following may give some indication as to how large the crowds were at the Passover feasts:
“would you desire to know what multitudes were at Jerusalem of the priests, you may know, as it is written, (1 Kings 8:63), and the tradition is, that an ox was offered for twenty four, and a sheep for eleven. —King Agrippa sought to know what was the number of the multitude, which were in Jerusalem; he said to the priests, lay by for me one kidney of every passover lamb; they laid by for him six hundred thousand pair of kidneys, double the number of those that came out of Egypt: and there is never a passover lamb, but there are more than ten numbered for it.”
Echa Rabbati, fol. 42. 3, 4 qt’d in Gill
This may be exaggerated since Josephus speaks of a crowd exceeding 2,7000,000. It has been estimated that the city could accommodate 150,000, so the remainder had to find lodging in the surrounding towns.
This crowd is of the country people who had come for the feast, most of them probably from Galilee, which was the center of most of the ministry of Jesus. Their enthusiasm for the coming of Jesus can be explained by this fact and that for quite some time many of them had felt that the teaching and miracles of Jesus had shown that He was the Messiah, even though He had not claimed such to this point.