So Jesus said to them, "When you lift up the Son of Man, then you will realize that I AM. (Jn 8:21-30)
https://bible.usccb.org/bible/readings/032823.cfm
The Fourth Gospel has the highest Christology (understanding of Christ) in the New Testament. The phrase “I AM” reminds us of the passage in the Book of Exodus when God answers Moses and says, “This is what you will tell the Israelites: I AM has sent me to you” (Ex 3:14). Jesus being lifted up is the moment of revelation. We behold the Cross and begin to understand and so are caught up in the mystery.