True Faith Is Faith In God's Promises (Hebrews 11:1-2).
Hebrews 11:1-2, ‘Now faith is assurance (hupostasis - ‘the substance' or ‘the underpinning' and therefore the ‘assurance', the ‘guarantee within the heart') of things hoped for, a proof (or ‘conviction') of things not seen, for therein the elders had witness borne to them.'
Faith is to see as substantial fact what is hoped for on the basis of taking God's promises seriously. It is to be assured of it, and to be convinced that what God has declared will be, seeing it as proved because He said it, even when it has not yet come about and is invisible. Thus it is to accept it as proved, on the basis of His word. Faith underpins hope in respect to what God has promised. Hope looks at what is to come with confidence, faith is satisfied that it will be so. The one who believes is satisfied that God has some better thing for him which is at present unseeable.
This was what believers of ancients times did and that is why we have a record of their lives. Faith is to hear God's word spoken by His Spirit and to respond to it. These people did not act on a whim or a conjured up belief, but on the solid basis of revelations received from God, and of the word of God, sometimes spoken, sometimes written, as it was communicated through the prophets, Abraham, Moses, and the like (see Hebrews 1:1). They believed God and responded accordingly.
‘The elders, the ancients.' These are those who lived in ancient times who had witness borne to them by God of things hoped for and things not seen, which they accepted as sure through their faith, and which they passed on down to us (Hebrews 1:1). Our faith is in part thus based on the valid religious experience of men as it has been established through history (Hebrews 1:1), religious experience which testifies to itself in our hearts. But additionally, in these last days, as the writer has been emphasising, it is faith in the Son Who has come and revealed Himself through His life and teaching, and through His death and resurrection (Hebrews 1:2-3; Hebrews 2:5-18).
Throughout his letter he has laid great emphasis on our hope (Hebrews 3:6; Hebrews 6:11; Hebrews 6:18-19; Hebrews 7:19), and now he confirms that having faith is living in response to that hope, because we see that it is a certain hope. It is having confidence in God's promises. It is also having certainty about what God is, again as revealed through His word as spoken by the Holy Spirit (that the writer sees the Scriptures as the words of the Holy Spirit he has constantly reminded us, specifically in Hebrews 3:7; Hebrews 9:8 and more generally in every one of his many Biblical quotations).