I believe Jesus was claiming to be the Messiah that was promised to come since before Abraham. Abraham "rejoiced to see Jesus' day," he knew the Messiah would come.
"Let us make man"... Jesus was there in the beginning. Remember when the Jews asked him how could He know Abraham who had long been dead? Jesus claimed to be God when He said "I AM". The Jews knew this. They asked who He thought He was, claiming to be God.