Bible Gateway:
https://www.biblegateway.com/passage/?search=Hebrews+11&version=AMP

Bible Hub Commentary Hebrews 11:1:
http://biblehub.com/commentaries/hebrews/11-1.htm
Ellicott's Commentary for English Readers
(1) We have seen how the writer approached the subject which is the chief theme of this last division of this Epistle. The coming of the Lord, for judgment upon His adversaries, for salvation to His people, draws nigh. In the midst of dangers and judgments God’s righteous servant shall live, and the ground, of his life is his steadfast faith—if he shrink back, destruction will overtake him. “Our principle of action” (the writer says to his Hebrew readers) “is not shrinking back, but faith. And faith is this. . . .”

It has been debated whether that which follows is a definition of what faith is, or in reality a description of what faith does. It is not a complete definition, in the sense of including all the moments of thought which are present in the word as used in the last chapter (Hebrews 11:38) or in this. The “things hoped for” are not mere figments of the imagination; their basis is THE WORD OF GOD. If we keep this in mind, the words, still remaining general in their form, agree with all that has led up to them and with all that follows; and whether they be called definition or description will be of little consequence.