What this page covers
What does the Bible mean by faith, and how does faith relate to trust and doubt?
This page is both the family overview and the Faith topic: faith as trust in God, its relationship to doubt, and how it shows itself in action. Trust in hard times is developed under Difficult times.
In Scripture, faith is mostly about trust — reliance on God and on His promises — rather than simply agreeing that certain statements are true. Hebrew uses words related to firmness (the root of amen); the New Testament’s pistis can be translated faith, trust or faithfulness.
Faith and doubt
One of the most honest prayers in the Gospels is a father’s: “I believe. Help my unbelief!” (Mark 9:24). Jesus does not send him away for his doubt; He answers the prayer. Scripture is full of people whose trust wavered — Abraham, Moses, Elijah, Thomas — and who were not abandoned for it.
Faith that grows
Faith is described as something that can grow, mainly through hearing God’s word (Romans 10:17). Jesus says that even a mustard seed’s worth can move mountains (Matthew 17:20): the point is not how much faith a person has but in whom it is placed.
Faith and works
Paul writes that people are saved by grace through faith, “not of works” (Ephesians 2:8–9); James writes that faith without works is dead (James 2:17). Both appeal to Abraham and Genesis 15:6. Christians have read this pairing differently. Many Protestant traditions emphasize that justification is by faith alone, with works as its fruit. Catholic teaching emphasizes faith working through love (Galatians 5:6), with grace preceding and enabling both. In 1999 the Catholic Church and the Lutheran World Federation signed a Joint Declaration on the Doctrine of Justification describing a shared basic understanding while noting remaining differences. The question on grace explains this more fully.
The faith family
Topics under Faith & trust will grow over time. For trusting God when life is hard, see Difficult times and the guide on the Psalms of lament.
Passages, in context
Now faith is assurance of things hoped for, proof of things not seen.
Est autem fides sperandarum substantia rerum, argumentum non apparentium.ad Hebræos 11:1 · Clementine Vulgate
The Bible’s nearest thing to a definition: faith as “assurance of things hoped for, proof of things not seen.”
Introduces the “hall of faith” in Hebrews 11
Immediately the father of the child cried out with tears, “I believe. Help my unbelief!”
Latin correspondence unavailable for this passage.
“I believe. Help my unbelief!” A father’s honest prayer — faith and doubt in one breath, and Jesus answers it.
A father asking Jesus to heal his son
He believed in the Lord, who credited it to him for righteousness.
Credidit Abram Deo, et reputatum est illi ad justitiam.Genesis 15:6 · Clementine Vulgate
Abraham believed God, and it was counted as righteousness — the verse Paul and James both build on.
God’s promise to Abram
So faith comes by hearing, and hearing by the word of God.
Ergo fides ex auditu, auditus autem per verbum Christi.ad Romanos 10:17 · Clementine Vulgate
Faith comes from hearing — it grows through encountering God’s word.
Paul to the church in Rome
for by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, that no one would boast.
Gratia enim estis salvati per fidem, et hoc non ex vobis: Dei enim donum est: non ex operibus, ut ne quis glorietur.ad Ephesios 2:8–9 · Clementine Vulgate
Salvation by grace through faith, as a gift, not an achievement.
Paul to the Ephesians
Even so faith, if it has no works, is dead in itself.
Sic et fides, si non habeat opera, mortua est in semetipsa.Jacobi 2:17 · Clementine Vulgate
Faith without works is dead: genuine trust shows itself in action.
The Letter of James
Without faith it is impossible to be well pleasing to Him, for he who comes to God must believe that He exists, and that He is a rewarder of those who seek Him.
Sine fide autem impossibile est placere Deo. Credere enim oportet accedentem ad Deum quia est, et inquirentibus se remunerator sit.ad Hebræos 11:6 · Clementine Vulgate
Without faith it is impossible to please God: faith as coming to God trusting that He is and that He rewards those who seek Him.
Hebrews 11
He said to them, “Because of your unbelief. For most certainly I tell you, if you have faith as a grain of mustard seed, you will tell this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you.
Latin correspondence unavailable for this passage.
Faith as small as a mustard seed: what matters is its object, not its size.
Jesus to His disciples after a failed healing
for we walk by faith, not by sight.
(per fidem enim ambulamus, et non per speciem):2 ad Corinthios 5:7 · Clementine Vulgate
We walk by faith, not by sight.
Paul on living toward what is unseen
How this differs from related topics
Faith is the posture of trust; Hope is the confident expectation that grows from it. “Trusting God in difficult times” is treated in a guide and on the Difficult times page. Questions about salvation and grace are addressed in the question on grace.