Instances of
Father of a possiosed son - "help me overcome my unbelief!" - Mark 9:24
Jesus - "Do you believe that I am able to do this?" - Matthew 9:28
Jesus - "You believe at last!" - John 16:31
Jesus - ignoring others, he said, "Don't be afraid; just believe." - Mark 5:36
Jesus - rebuked them for their lack of faith and their stubborn refusal to believe those who had seen him - Mark 16:14
Ninevites - believed God after Jonah call them to repentance - Jonah 3:5
Peter - stopped focusing on Jesus and began to doubt - Matthew 14:25, 26, 27, 28, 29, 30, 31
Satan - putting doubt in Eve's mind about what God said - Genesis 3:1
Zechariah - not believing angel became silent - Luke 1:18, 19, 20