He made a trick: he left every word "God" as a blank space, then he wrote in the blank space an invisible writing using the colorless silver nitrate solution.
He told the Jews that God Himself will write that blank space, then when they saw the writing of those words, they believed him and started to sanctify him.
Some said that God wrote the Tablets for Moses, and He also wrote the blank space for Ezra .. so Ezra is preferred by God .. therefore, they started to glorify him .. at that time some said Ezra is like Moses, then others said: he is greater than Moses: for to Moses the Tablets were written .. while to Ezra the whole Torah is confirmed .. and so they went on glorifying him until they said Ezra is the son of God.
This was in the past.
This video explains about this trick