Faith, or faithfulness (which may be a better representation of pistis) is a distinctive characteristic of the people of God. Some of the elements of this faithfulness are loyalty, risk-taking, sometimes radical disobedience to authorities , persistance and cross-carrying; and it is deeply rooted in the principles of justice, equity and fairness. I said earlier:
Faith is a lifestyle - not a dogma. It's not about what people think, but about what they do.
In modern usage the word "faith" is oftened preceeded by the definite article "the" to refer to doctrinal orthodoxy - "the Faith" - and is often used as a kind of shorthand to refer to the one, true, apostolic faith. To have fellowship with the people of God, one must understand and give assent to the faith, usually defined in a Statement of Faith, or a Declaration of the Faith, or similar.
The translators of the New International Version, for example, have gone for this usage in translating Matthew 24:10, where they have "many will turn away from the faith" even though the Greek does not contain the word pistis at all. In fact, the KJV and most other translations render it more literally as "many will be offended" or "many will stumble". The Greek word is skandalizo and means to be trapped, ensnared, tripped up, to stumble, or be enticed [to sin]. It does not refer to "the faith" at all. The NIV translators got this one wrong.
There is only one place in the Gospels where the word pistis may have the possible meaning of "the faith" as kind of creedal faith, or as "religion" rather than "trust". In Luke 18:8 Jesus asks the rhetorical question: "when the Son of Man comes, will he find [the] faith on the earth?" The NIV translators at least got it right here and avoided the definite article - "will he find faith on the earth?" The context is about faithfulness and God bringing about "justice for his chosen ones, who cry out to him day and night". However, some Christadelphians prefer to read this as "the faith" to support a remnant theology that says that only a relative handful of people will believe "the Truth" in the last days prior to the Lord's return. I touched on this in an earlier post: there is absolutely no Biblical evidence, in my opinion, for a remnant theology which says "the Truth" or "the Faith" will progressively be perverted and apostasised so that hardly any at all will accept it at the end (if you want me to deal with this in more detail please email me). In this verse Jesus is simply asking a rhetorical question: when the Son of Man comes will He find the kind of persevering faith or faithfulness He just talked about. There is no hint of a suggestion here that the "one true apostolic Faith" will have disappeared, or almost disappeared, by the time of the Second Coming.
Having examined every reference to pistis/pisteuo in the Gospels I can confidently assert that Jesus never referred to "the faith" as a set of doctrinal statements, or a system of belief or theology, or fundamentals/foundations/first principles of things which must be believed in order to belong to the people of God. To Him "faith" meant a practical trust in the power of God to provide and to meet physical needs.
In my next post I would like to address what the other writers of the New Testament wrote about faith.