Omni

verse 7 - "...the Lord...did spare the righteous that they should not perish, but did deliver them out of the hands of their enemies..."
If we are living the way we should, we will not be destroyed, at least spiritually...which is what really counts.  None will He destroy that believe in Him (2 Nephi 6:14).

verse 17 - "...and their language had become corrupted; and they had brought no records with them..."
The two portions of this excerpt may be very closely related.  A BYU Professor did a study on the words in the Book of Mormon, and found that reading the Book of Mormon helps improve reading and language skills.  Interesting - not only are we fed spiritually, but we also improve our literacy.  Reading the Book of Mormon in French sure helped me learn French quicker! (Mosiah 1:2-5)

verse 25 - "...for there is nothing which is good save it comes from the Lord: and that which is evil cometh from the devil..."
This is a good standard to compare to.  If the things that we are doing persuade, or entice us to do good, then it comes from the Lord, but if it entices us to do evil, that's from the devil (2 Nephi 2:16).
We would not do anything unless we were enticed to do it...so we need to look for the good enticements and remove as many of the evil ones as we can out of our lives.

verse 25 - "...believe in prophesying, and in revelations, and in the ministering of angels, and in the gift of speaking with tongues, and in the gift of interpreting languages, and in all things which are good..."
Part of the key here is believing in these blessings and manifestations of the Spirit.  God wants to give these blessings to us and help us grow and progress, especially in helping others...but it requires faith.  Often we miss out on these blessings because we don't believe we'll receive.  We need to exercise our faith!