Neither could the 5000 that left him. Why? Because they did not understand. Which do you want to be? The one who stayed with him or the one that walked away? The Apostles did not understand either. They believed because it Jesus who spoke and they knew he had the words of eternal life.
It is not a ritual that saves us, Publisher, it is Jesus Christ who chose this manner to remain with us until the end of time and to feed us with the Bread of Life; his own glorified body, blood, soul and divinity. It is how we come into union with God.
Don’t take our word for it. Just listen to the words of Jesus himself. "“Very truly I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you.”