This is a question that has been debated for millennia by the church and theologians.
Hebrews 11:1 says:
Faith is the assurance of things hoped for, the conviction of things not seen.
So what are we hoping for and convicted that it’s true but not seeing?
When looking at the concept of faith we have to connect it to salvation. A person who has accepted Christ has the assurance of spending eternity with God the Father and a conviction that the work of Christ is enough to ensure this eternity.
The Protestant Reformation of the 16th century dealt with this concept of faith and eternal life.
Martin Luther, one of the initiators of this movement believed that man was justified through faith, i.e., man was saved through their faith in Christ. However the Catholic Church reacted and asked the question, “Does that mean a person can just believe in Jesus and then live any way they want to?”
This important question caused those early reformers to carefully define what it meant to have faith. They came up with three Latin terms.
The first term is notitia. It means to believe in the data. It is impossible to have faith in nothing; therefore there must be something to believe in. With reference to Christ, it is vital to believe He is the Son of God, sent to earth to take on the sins of mankind.
Jesus died for humanity and rose again three days later having conquered death and is now sitting at the right hand of God.
This would be some of the data the early reformers were talking about. Beyond believing in the data, there must be intellectual assent.
This brings up the second term that came from this 16th century movement – assensus. To have assensus a person must be persuaded of the truthfulness of the content.
Many religions around the world believe Jesus really lived and was a good man teaching good things, yet do not consider him to be the Son of God.
It says in James 2:19 that the devil believes but he doesn’t have saving faith.
So man must believe the data and then intellectually assimilate it.
Finally, there must be fiducia. This Latin word means that man should have a fiduciary commitment with Christ and put his life in His hands. Many who have done business transactions have entered into a fiduciary or a legal relationship of trust between two or more parties.
That is what humanity must do with Christ to accept Him.
It is not enough to just know the data. It is not enough to intellectually agree with or accept the information. To have faith in Christ and ensure salvation and eternity with God the Father one must allow Jesus to guide and control his life.
There must be an agreement or relationship in which God takes control of the direction of your life. If any of these three criteria are missing, then your faith is incomplete and will not lead to salvation in Christ.