What Is Faith in the Bible? Hebrews 11 and the Substance of Hope

The Foundation: Defining Faith in Hebrews 11:1

To truly grasp what is faith in the Bible, we must start at the definitive source: Hebrews 11:1. The author writes, 'Now faith is the assurance of things hoped for, the conviction of things not seen.' In the original Greek, the word for 'assurance' is 'hupostasis,' which literally means a foundation or a substructure. It is the concrete slab that holds up the entire house of our Christian walk.

This means that faith isn't a nebulous cloud of emotion. It is a solid reality. It is the 'conviction' or evidence of things we cannot yet touch or see. Just as you trust the chair you are sitting in to hold your weight because of its design and history, biblical faith is a settled confidence in the character of God. It is looking at the invisible promises of God and treating them as more real than the visible world around us.

Faith Is More Than Mental Agreement

A common misconception is that faith is simply agreeing that certain facts about Jesus are true. While intellectual assent is part of the process, James 2:19 reminds us that even the demons believe there is one God—and they shudder. True biblical faith involves the heart, the mind, and the will. It is an active entrustment of one's self to God.

Think of it like a bridge. You can stand on the bank of a river and believe with all your heart that the bridge is structurally sound. You can study the blueprints and admire the engineering. However, you don't actually exercise faith in that bridge until you step onto it and allow it to carry you across. In the same way, understanding what is faith in the Bible requires us to move from knowing about God to personally relying on Him.

The Witness of the Ancients: Learning from the Hall of Faith

Hebrews 11 is often called the 'Hall of Faith' because it lists men and women who lived out this 'substance of hope.' From Abel to Rahab, the chapter showcases a diverse group of people who had one thing in common: they took God at His word, even when their circumstances suggested otherwise. Noah built an ark when there was no sign of rain; Abraham left his home for a land he had never seen.

These stories teach us that faith is often counter-cultural and counter-intuitive. It doesn't always make sense to the world. Sarah's faith wasn't in her own ability to conceive, but in the faithfulness of the One who had promised (Hebrews 11:11). When we look at these witnesses, we see that faith is not a superpower reserved for the 'elite' saints; it is a persistent trust available to anyone who looks toward God.

Why Faith Requires 'Things Not Seen'

We live in a culture that demands proof before commitment. We want to see the ROI (return on investment) before we buy in. However, the Bible teaches that 'we walk by faith, not by sight' (2 Corinthians 5:7). If we could see the outcome, we wouldn't need faith. The 'not seen' element is exactly where our relationship with God grows.

This doesn't mean faith is blind. It is based on the 'seen' faithfulness of God in the past—specifically the life, death, and resurrection of Jesus. Because we have seen what He did at the Cross, we can trust Him for the 'unseen' future. Faith is the bridge between the memory of God’s past goodness and the hope of His future glory. When you are in a dark valley, faith is the flashlight that reveals just enough of the path to take the next step.

Practical Steps: How to Cultivate Biblical Faith

If you find yourself struggling to believe, take heart. Even the disciples cried out, 'Increase our faith!' (Luke 17:5). The first practical step is to immerse yourself in the Word of God. Romans 10:17 tells us that 'faith comes from hearing, and hearing through the word of Christ.' You cannot trust a God you do not know, and you cannot know Him apart from His Word.

Secondly, practice small acts of obedience. Faith is like a muscle; it grows stronger when it is used. When you feel a nudge from the Holy Spirit to give, to serve, or to forgive, and you choose to obey despite your feelings, your faith is strengthened. Lastly, stay connected to the body of Christ. We are encouraged by the faith of others, which is why Hebrews 12:1 tells us we are surrounded by such a 'great cloud of witnesses.'

The Object of Our Faith Matters Most

It is a common mistake to focus on the 'size' of our faith. We worry that we don't have 'enough' faith to get through a trial. But Jesus said that even faith as small as a mustard seed can move mountains (Matthew 17:20). The power of faith does not reside in the person exercising it, but in the Object toward whom it is directed.

A person with great faith in a thin sheet of ice will fall through. A person with tiny, trembling faith in a thick, solid sheet of ice will be safe. The goal of the Christian life isn't to have 'faith in faith,' but to have faith in a sovereign, loving, and all-powerful God. When you feel your faith wavering, stop looking at your own heart and start looking at the character of Jesus, the 'founder and perfecter of our faith' (Hebrews 12:2).

Faith in the Midst of Suffering

Perhaps the hardest time to understand what is faith in the Bible is when we are suffering. We often think faith means God will always deliver us from the fire. However, Hebrews 11:35-39 tells us of many who were tortured, mocked, and killed, yet they are commended for their faith. Their faith didn't give them an escape; it gave them the strength to endure.

Biblical faith allows us to say, like Job, 'Though he slay me, I will hope in him' (Job 13:15). It is the quiet confidence that God is working all things together for good, even when the 'good' isn't visible in this lifetime. This 'substance of hope' anchors our souls so that we aren't tossed about by the changing winds of our circumstances. We trust not in a comfortable life, but in a faithful God.

Final Thoughts

Faith is not a final destination we reach in this life, but a rhythmic way of walking with a God who has proven Himself trustworthy. As we look at the 'great cloud of witnesses' in Hebrews 11, we are reminded that our faith is part of a much larger story.

Today, take one small step of trust. Whether it is praying about a hidden worry or obeying a difficult command, remember that the substance of your hope is not found in your own strength, but in the finished work of Jesus Christ.

Continue your study with our companion guide: What Does the Bible Say About Death? Hope Beyond the Grave.