Short answer: In the Bible, faith is confident trust in God and His promises — not blind belief without reason, but reliance on a trustworthy God. Hebrews 11:1 defines it, Ephesians 2:8 says it saves, and passages like Romans 10:17 and Matthew 17:20 show how it grows and what it can do.
The context: how the Bible defines faith
The clearest definition is Hebrews 11:1 (WEB): "Now faith is assurance of things hoped for, proof of things not seen." Faith is not certainty about everything; it is trust that the unseen God is real and reliable. The whole of Hebrews 11 then lists ordinary people — Abraham, Sarah, Moses, Rahab — who acted on that trust. In Scripture, faith is shown as much by what people do as by what they say they believe.
What the Bible says about faith
Faith is how we are saved. Ephesians 2:8–9 states that we are saved "by grace... through faith," and that this is "the gift of God, not of works." Faith is the empty hand that receives what God gives, not a work that earns it.
Faith comes by hearing God's Word. Romans 10:17 says faith comes "by hearing, and hearing by the word of Christ." Faith is not manufactured by willpower; it grows as we take in Scripture.
Small faith can still move mountains. In Matthew 17:20 Jesus says faith "as a grain of mustard seed" can move a mountain. The point is not the size of our faith but the greatness of its object — a small trust in a great God accomplishes much.
Faith pleases God. Hebrews 11:6 declares that "without faith it is impossible to be well pleasing to him," because anyone who comes to God must believe that He exists and rewards those who seek Him.
Faith and works belong together. James 2:17 warns that "faith, if it has no works, is dead in itself." Genuine faith naturally produces action and love — the two are not rivals but partners.
Cross-references worth reading
- 2 Corinthians 5:7 — "we walk by faith, not by sight."
- Galatians 2:20 — living "by faith in the Son of God."
- Mark 9:24 — the honest prayer, "I believe. Help my unbelief!"
- Romans 1:17 — "The righteous shall live by faith."
- 1 Peter 1:7 — faith tested and refined like gold.
How to apply it today
If your faith feels small, Scripture offers encouragement rather than shame. Faith grows through hearing God's Word (Romans 10:17), so regular time in the Bible feeds it. It also grows through use: Abraham's faith was strengthened by acting on God's promises step by step. And it can coexist with doubt — the father in Mark 9:24 prayed "help my unbelief," and Jesus honored that honest, mixed faith. Start where you are, feed it, and act on it.
Frequently Asked Questions
What is the biblical definition of faith? Hebrews 11:1 defines faith as "assurance of things hoped for, proof of things not seen." It is confident trust in God and His promises, especially regarding things we cannot yet see. Biblical faith is directed at God's character, so its reliability depends on Him, not on the strength of our feelings.
How do I grow my faith according to the Bible? Romans 10:17 says faith comes through hearing God's Word, so Scripture intake is central. Faith also strengthens through prayer, obedience, and acting on what God has said, as the examples in Hebrews 11 show. Community and remembering God's past faithfulness help sustain it as well.
Can you have doubts and still have faith? Yes. Mark 9:24 records a man crying, "I believe. Help my unbelief!" and Jesus responds with mercy. Faith and doubt often coexist. The Bible treats honest wrestling as part of a real relationship with God rather than a disqualification from it.