Start with the text.
World English Bible Updated · public domain. The passages below are source text, not AI quotations.
Mark 9:20-27 Read passage
20They brought him to him, and when he saw him, immediately the spirit convulsed him and he fell on the ground, wallowing and foaming at the mouth.
21He asked his father, “How long has it been since this has been happening to him?” He said, “From childhood.
22Often it has cast him both into the fire and into the water to destroy him. But if you can do anything, have compassion on us and help us.”
23Jesus said to him, “If you can believe, all things are possible to him who believes.”
24Immediately the father of the child cried out with tears, “I believe. Help my unbelief!”
25When Jesus saw that a multitude came running together, he rebuked the unclean spirit, saying to him, “You mute and deaf spirit, I command you, come out of him, and never enter him again!”
26After crying out and convulsing him greatly, it came out of him. The boy became like one dead, so much that most of them said, “He is dead.”
27But Jesus took him by the hand and raised him up; and he arose.
John 20:24-29 Read passage
24But Thomas, one of the twelve, called Didymus, wasn’t with them when Jesus came.
25The other disciples therefore said to him, “We have seen the Lord!” But he said to them, “Unless I see in his hands the print of the nails, put my finger into the print of the nails, and put my hand into his side, I will not believe.”
26After eight days, again his disciples were inside and Thomas was with them. Jesus came, the doors being locked, and stood in the middle, and said, “Peace be to you.”
27Then he said to Thomas, “Reach here your finger, and see my hands. Reach here your hand, and put it into my side. Don’t be unbelieving, but believing.”
28Thomas answered him, “My Lord and my God!”
29Jesus said to him, “Because you have seen me, you have believed. Blessed are those who have not seen and have believed.”
Psalm 13:1-6 Read passage
1How long, LORD? Will you forget me forever? How long will you hide your face from me?
2How long shall I take counsel in my soul, having sorrow in my heart every day? How long shall my enemy triumph over me?
3Behold, and answer me, LORD, my God. Give light to my eyes, lest I sleep in death;
4lest my enemy say, “I have prevailed against him;” lest my adversaries rejoice when I fall.
5But I trust in your loving kindness. My heart rejoices in your salvation.
6I will sing to the LORD, because he has been good to me.
Read this in context.
Mark 9 narrates a parent seeking help for a suffering child after the disciples could not help. John 20 follows Jesus’ resurrection and the disciples’ testimony. Psalm 13 gives a prayer of distress that does not begin with emotional certainty.
What we can observe.
The parent in Mark 9:24 voices both belief and unbelief. Thomas is absent at the first encounter in John 20:24. Jesus later addresses the evidence Thomas asked for and speaks about those who believe without seeing.
A reading to consider.
Questions can be brought honestly into study, prayer, and community. These passages do not settle every philosophical question, but they resist pretending no faithful person ever wrestles with uncertainty.
Where Christians differ.
This guide focuses on the shared textual observations above rather than a survey of denominational positions. It does not claim that every Christian interprets every detail alike.
Read it for yourself.
What is the specific question beneath the word “doubt” that you want to examine carefully?
A question of your own?
Take what you have read into a guided study. Begin with the passages, explore their context, and keep room for your own reflection.