3 Definitions of “What is faith?”

Hebrews 11:1,

Faith is the substance of things hoped for, the evidence of things not seen.

The New International Version says, Faith is being sure of what we hope for and certain of what we do not see. 

1 Timothy 6:12,
 
Fight the good fight of [the substance of things hoped for, the evidence of things not seen. Fight the good fight of being sure of what you hope for and being convinced of what you do not see.]

I don’t care what the world says, I don’t care what circumstances say, I am going to fight the good fight of the substance of things hoped for, the evidence of what I do not see.”
 
And you stay with it until, as they say, “Faith turns to sight.”