Faith and repentance are the two essential components of responding to the gospel in a saving way.
Even so, Australian preacher Phillip Jensen1 avoids the word ‘faith’ in gospel presentations because it is “a misused and misunderstood religious word if ever there was one.”2 Preachers need to communicate Scriptural truth in ways that listeners understand. Sometimes that means actively fighting misunderstanding.
In modern English, faith means believing something to be true even though all the evidence is against you. Faith is a kind of blind, irrational leap (usually into the dark) in the face of all that is reasonable. This is reflected in the Concise Oxford Dictionary, which defines faith as ‘belief in religious doctrines, especially such as effects character and conduct; spiritual apprehension of divine truth apart from proof’.
The Bible uses the word ‘faith’ to mean simply ‘trust’. To have faith in someone is to trust them, or rely on them, or be confident that what they say is true. You may do this rationally on the basis of detailed evidence, or you may do it irrationally because you are gullible; but either way it qualifies as ‘faith’.
As I write this, I am believing in a chair. I am having faith in it. My whole weight is placed upon it and I am trusting in it to do its job. It is not an irrational faith. I have been sitting on this chair for some part of most days during the last fifteen years, and it has yet to fail me. If I felt so inclined, I could examine the chair more closely to see if it was worthy of my trust. I could test its construction, analyse its design, and check all the joints. If it passed all the tests, I could then choose to sit on it, with my empirical rationality finally satisfied. However, I would still be putting faith in the chair (and, incidentally, in my empirical rationality).
Now faith understood in this sense (as trust or confidence) lies at the heart of our response to God. The gospel declares to us who Jesus is and what he has done. It tells of God’s plans for the world and for each one of us, and it calls on us to turn from our present way of life (repent) and place our trust in Jesus (faith). Like the Thessalonians, we are to ‘wait for [God’s] Son from heaven’; that is, to put our ‘faith’ in him (1 Thess 1:10).
1 If you are unfamiliar with Jensen, familiarize yourself by browsing his books, Bible studies, or gospel tracts, including the popular Two Ways to Live.
2 Phillip Jensen in Guidance and the Voice of God, Kindle Location 356