A.T. Robertson Commentary Mark 8:32

"And he spake the saying openly. And Peter took him, and began to rebuke him." — Mark 8:32 (ASV)

Spake the saying openly (παρρησια τον λογον ελαλε). He held back nothing, told it all (παν, all, ρησια, from ειπον, say), without reserve, to all of them. Imperfect tense ελαλε shows that Jesus did it repeatedly. Mark alone gives this item. Mark does not give the great eulogy of Peter in Mt 16:17,19 after his confession (Matthew 16:16; Luke 9:20), but he does tell the stinging rebuke given Peter by Jesus on this occasion. See discussion on Mt 16:21,26.