'''Faith''' means to believe in the truth of an idea that cannot be proven. [[Hebrews 11:1]] in the Bible describes faith as being sure of something that is unseen.
The term "the faith" is sometimes used to refer to [[Christianity]] in general.
Faith in [[Jesus]] as God's son who brings eternal life is central to being a Christian. [[John 3:16]] describes this truth:
: ''{{Bible verse|John|3|16|lang=WEB}}''
In the Christian philosophical tradition which originated in the Middle Ages, especially through the work of [[Thomas Aquinas]], faith is defined as one of the three so-called "theological virtues"<ref>For an introduction to the theological virtues cf. Josef Pieper: Faith, Hope, Love, Ignatius Press 1997, ISBN 0898706238</ref> that were described by the [[apostle Paul]] in [[1 Corinthians 13:13]] in the [[Bible]]: