What the Bible says about Mysteries of Salvation
(From Forerunner Commentary)
Verse 52 shows that the Jews again interpret His words in a strictly literal sense: "How can this Man gives us His flesh to eat?" How utterly impossible it is for those who do not believe, who do not "come to Him," to understand the mysteries of salvation! Their hearts are ever ready to quarrel, scoff, and resist.
Jesus does not back down in the face of their scoffing. Instead, He strengthens His statement about eating His flesh by adding that one must also drink His blood! He moves from something that seems foolish to His audience to the outright absurd.
John W. Ritenbaugh
Eating: How Good It Is! (Part Four)