Hebrews 10 & 11

Paul introduces one of the greatest text on faith with patience as he writes the Hebrews -

"Cast not away therefore your confidence, which hath great recompence of reward.
36 For ye have need of patience, that, after ye have done the will of God, ye might receive the promise." (New Testament Hebrews 10:35 - 36)

Faith is demonstrated as we do the will of God. Paul tells us that -

"...without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him." (New Testament Hebrews 11:6)

And also that -
"....the just shall live by faith: but if any man draw back, my soul shall have no pleasure in him." (New Testament Hebrews 10:38)

To me, to "draw back" means to not exhibit sufficient faith to do His will. For -

"...faith is the substance of things hoped for, the evidence of things not seen." (New Testament Hebrews 11:1)

Substance in this case meaning assurance, basis, or foundation. In the Joseph Smith Translation the word ing "...the assurance of things hoped for..." It is through faith or doing the will of God that -

"...the elders obtained a good report." (New Testament Hebrews 11:2)

or personal witness or testimony by the Spirit. Paul recounts many of the acts of faith by great men in the old testament. But was there ever a greater act of faith than -

"...Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son..." (New Testament Hebrews 11:17)

Abraham being one -

"...who had offered sacrifice in the similitude of the great sacrifice of the Son of God, and had suffered tribulation in their Redeemer's name." (Doctrine and Covenants Section 138:13)

Abraham as well as many saints, -

"...these all, having obtained a good report through faith..." (New Testament Hebrews 11:39)

All having faith, so demonstrated by doing the will of God.