A.T. Robertson Commentary Mark 16:14

"And afterward he was manifested unto the eleven themselves as they sat at meat; and he upbraided them with their unbelief and hardness of heart, because they believed not them that had seen him after he was risen." — Mark 16:14 (ASV)

To the eleven themselves (αυτοις τοις ενδεκα). Both terms, eleven and twelve (John 20:24), occur after the death of Judas. There were others present on this first Sunday evening according to Lu 24:33.

Afterward (υστερον) is here alone in Mark, though common in Matthew.

Upbraided (ωνειδισεν). They were guilty of unbelief (απιστιαν) and hardness of heart (σκληροκαρδιαν). Doubt is not necessarily a mark of intellectual superiority. One must steer between credulity and doubt. That problem is a vital one today in all educated circles. Some of the highest men of science today are devout believers in the Risen Christ. Luke explains how the disciples were upset by the sudden appearance of Christ and were unable to believe the evidence of their own senses (Luke 24:38–43).