"And he also testified unto the people that all mankind should be saved at the last day, and that they need not fear nor tremble, but that they might lift up their heads and rejoice; for the Lord had created all men, and had redeemed all men; and, in the end, all men should have eternal life. (Alma 1:4)
"But as to the people that were in the land of Ammonihah, they yet remained a hard-hearted and a stiffnecked people; and they repented not of their sins, ascribing all the power of Alma and Amulek to the devil; for they were of the profession of Nehor, and did not believe in the repentance of their sins." (Alma 15:15)
"Not withstanding they believed in a Great Spirit, they supposed that whatsoever they did was right." (Alma 18:5)
"And many more such things did he say unto them, telling them that there could be no atonement made for the sins of men, but every man fared in this life according to the managment of the creature; therefore every man prospered according to his genius, and that every man conquered according to his strength; and whatsoever a man did was no crime." (Alma 30:17)
What These Verses Imply
All of mankind will not be saved. There will be those who will not inherit eternal life - ever.
Believe in repentance - it will save you.
We cannot do anything we want. There are consequences to our actions.
Christ could and did atone for our sins. The atonement is real.
We can commit crimes against the law of God.