In my answer to this realted question I point out that before Jesus "went public" so to speak his forerunner, the prophet John had acted as a kind of "shofar call" for all of Judea to repent and be ritually cleansed in water because the Messiah was going to come after John.
John explained that he was coming after him but he was more important than he was because he was the Messiah and was going to purge the land of all wickedness and bring about the glorious promises of the kingdom of God. John drew massive crowds because Messianic expectations were at fever pitch because the people were chafing under the oppressive Roman ruler and hoped for deliverance, as long promised. And more importantly because God was in the process of resurrecting Israel from their death and spiritual lethargy:
[Eze 37:11-14 KJV] 11 Then he said unto me, Son of man, these bones are the whole house of Israel: behold, they say, Our bones are dried, and our hope is lost: we are cut off for our parts. 12 Therefore prophesy and say unto them, Thus saith the Lord GOD; Behold, O my people, I will open your graves, and cause you to come up out of your graves, and bring you into the land of Israel. 13 And ye shall know that I [am] the LORD, when I have opened your graves, O my people, and brought you up out of your graves, 14 And shall put my spirit in you, and ye shall live, and I shall place you in your own land: then shall ye know that I the LORD have spoken [it], and performed [it], saith the LORD.
God had promised in a prophecy long before that he would send John before Jesus and that all who would repent, be ritually immersed and recognize the coming Messiah would be forgiven of their sins and that when Jesus came he would baptize them in God's holy spirit power:
[Mar 1:5 KJV] 5 And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins.
So my point is that Jesus was the promised Messiah and this was the beginning of the millennial reign, the ideal age of the Messiah.
And then of course there was his inspired teaching, miracles and such, the controversy swirling about him... he was and is a big deal:
One Solitary Life
Here is a man who was born in an obscure village, the child of a peasant woman. He grew up in another village. He worked in a carpenter shop until He was thirty. Then for three years He was an itinerant preacher.
He never owned a home. He never wrote a book. He never held an office. He never had a family. He never went to college. He never put His foot inside a big city. He never traveled two hundred miles from the place He was born. He never did one of the things that usually accompany greatness. He had no credentials but Himself...
While still a young man, the tide of popular opinion turned against him. His friends ran away. One of them denied Him. He was turned over to His enemies. He went through the mockery of a trial. He was nailed upon a cross between two thieves. While He was dying His executioners gambled for the only piece of property He had on earth – His coat. When He was dead, He was laid in a borrowed grave through the pity of a friend.
Nineteen long centuries have come and gone, and today He is a centerpiece of the human race and leader of the column of progress.
I am far within the mark when I say that all the armies that ever marched, all the navies that were ever built; all the parliaments that ever sat and all the kings that ever reigned, put together, have not affected the life of man upon this earth as powerfully as has that one solitary life.