1 Nephi 19

As Nephi taught his brethren the words and prophecies of Isaiah, he tells us -

"...I spake unto them, saying: Hear ye the words of the prophet, ye who are a remnant of the house of Israel, a branch who have been broken off; hear ye the words of the prophet, which were written unto all the house of Israel, and liken them unto yourselves, that ye may have hope as well as your brethren from whom ye have been broken off; for after this manner has the prophet written." (Book of Mormon | 1 Nephi 19:24)

It is evident that the words of Isaiah, are for "all the house of Israel" which house or "blood" has been spread through all nations. In other words, most people have the blood of Israel and considered to be of the house of Israel. Nephi explains why the words of Isaiah are so important -
"...that ye may have hope...for after this manner has the prophet written." (Book of Mormon | 1 Nephi 19:24)

The definition of hope in our day seems to suggest that "maybe" things would work out, but in regards the two thousand stripling warriors, Helaman explained -

"...that the Lord our God did visit us with assurances that he would deliver us; yea, insomuch that he did speak peace to our souls, and did grant unto us great faith, and did cause us that we should hope for our deliverance in him." (Book of Mormon | Alma 58:11)

I feel in these words that "assurance" is synonomous to "hope". This is the kind of that comes by faith assured by the Spirit. I believe the words of Isaiah provide hope or assurance to all the house of Israel. Is it any wonder the Savior commanded us -

"...Yea, a commandment I give unto you that ye search these things diligently; for great are the words of Isaiah." (Book of Mormon | 3 Nephi 23:1)