Expositor's Bible Commentary Commentary Mark 9:19

"And he answereth them and saith, O faithless generation, how long shall I be with you? how long shall I bear with you? bring him unto me." — Mark 9:19 (ASV)

It seems best to restrict the meaning of “unbelieving generation” to the disciples. Thus the cry of Jesus reveals his bitter disappointment with them; in the crucial moment they had failed because of their lack of faith during Jesus’ absence.

In the face of such unbelief, Jesus longed for his heavenly Father. He was weary with his disciples’ spiritual obtuseness. But in teaching them, Jesus never gave up. Mark seems particularly anxious to show him persisting in instructing them (9:30–31; 14:28; 16:7).