The difficulty for the hearers of Jesus teaching was that they did not understand the spiritual meaning of the words; “eat my flesh and drink my blood”. They heard only the physical act of eating Jesus flesh and drinking his blood.
John 6:53 Then Jesus said to them, “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you.
John 6:61 When Jesus knew in Himself that His disciples complained about this, He said to them, “Does this offend you?
Many of the things that Jesus spoke in the presence of larger crowds of people, were veiled in illustrations. When the Lord spoke privately to those who had already received Him as the Messiah, He spoke plainly and directly to the point. Why Jesus hid the true meaning of his teaching to large assemblies, is certainly important. In a large crowd, many would come just to see what all the activity was all about. Others had heard that Jesus was giving out food, healing, or other miracles. Some came simply for the spectacle, others to get something. There were however, a few who were looking for truth.