The Bible defines faith this way: "Faith is the substance of things hoped for, the evidence of things not seen" (Hebrews 11:1 Hebrews 11:1Now faith is the substance of things hoped for, the evidence of things not seen.
American King James Version×). In a world primarily dependent on the scientific method, where all facts must be tested and retested using observable, measurable evidence and empirical data, to claim that something as intangible as faith counts for both substance and evidence sounds ridiculous. But that, at its core, is faith.
In Hebrews 11 (and most places in the New Testament), faith is translated from the Greek word pistis, which can also be translated belief or assurance. To have faith is to believe God and trust Him. Faith can begin with seeing the wonders of the physical creation, which reveal our Creator's invisible attributes (Romans 1:20 Romans 1:20For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
American King James Version×; see Life's Ultimate Question: Does God Exist?). But faith must grow beyond that to become an active, living faith powered through the gift of God's Holy Spirit (James 2:18-20 James 2:18-20  Yes, a man may say, You have faith, and I have works: show me your faith without your works, and I will show you my faith by my works.  You believe that there is one God; you do well: the devils also believe, and tremble.  But will you know, O vain man, that faith without works is dead?
American King James Version×; Ephesians 2:8 Ephesians 2:8For by grace are you saved through faith; and that not of yourselves: it is the gift of God:
American King James Version×; Galatians 5:22 Galatians 5:22But the fruit of the Spirit is love, joy, peace, long-suffering, gentleness, goodness, faith,
American King James Version×).
The rest of Hebrews 11 proceeds to describe men and women who "died in faith, not having received the promises, but having seen them afar off were assured of them, embraced them and confessed that they were strangers and pilgrims on the earth" (Hebrews 11:13 Hebrews 11:13These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and confessed that they were strangers and pilgrims on the earth.
American King James Version×). Their faith in God's promises was so strong that they could see them in their minds' eye. Their future homeland, the Kingdom of God, was as real to them (arguably more real) as anything else around them.
The Bible says that "without faith it is impossible to please Him [God], for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him" (Hebrews 11:6 Hebrews 11:6But without faith it is impossible to please him: for he that comes to God must believe that he is, and that he is a rewarder of them that diligently seek him.
American King James Version×). Faith—absolute and unshakable trust that God's promises are true—is essential for entering God's Kingdom. Of the heroes of faith listed in Hebrews 11, we read, "Therefore God is not ashamed to be called their God, for He has prepared a city for them" (Hebrews 11:16 Hebrews 11:16But now they desire a better country, that is, an heavenly: why God is not ashamed to be called their God: for he has prepared for them a city.
American King James Version×). That promised eternal city takes faith to reach.
For more understanding, please read our Bible study aid booklet You Can Have Living Faith.