Matthew
King James Version (KJV)

“Then Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I suffer you? bring him hither to me.”
King James Version (KJV)
17:17 O unbelieving and perverse generation - Our Lord speaks principally this to his disciples. How long shall I be with you? - Before you steadfastly believe?
Mt 17:17 O faithless and perverse generation. Intended especially for the disciples who had failed in the cure from weakness of faith. How long shall I suffer you? Bear with your shortcomings. Bring him hither to me. The emphasis is upon "me". This act of mercy could have been done by his disciples had they been devout, prayerful and believing.