{Peter took him} (proslabomenos auton ho Petros). Middle
voice, "taking to himself," aside and apart, "as if by a right of
his own. He acted with greater familiarity after the token of
acknowledgment had been given. Jesus, however, reduces him to his
level" (Bengel). "Peter here appears in a new character; a minute
ago speaking under inspiration from heaven, now under inspiration
from the opposite quarter" (Bruce). Syriac Sinaitic for  Mr 8:32 
has it "as though pitying him." But this exclamation and
remonstrance of Peter was soon interrupted by Jesus. {God have
mercy on thee} (hile(9373). Supply ei(885c) or est(9320)ho theos). {This
shall never be} (ou m(8820)estai soi touto). Strongest kind of
negation, as if Peter would not let it happen. Peter had perfect
assurance.