JST Matthew 5:21 Whosoever, therefore, shall break one of these least commandments [the Sermon on the Mount] and shall teach men so to do, he shall in no wise be saved in the kingdom of heaven; but whosoever shall do and teach these commandments of the law until it be fulfilled, the same shall be called great and shall be saved in the kingdom of heaven.
The way to guaranteed salvation: do and teach all of the Lord's commandments in the Sermon on the Mount until you fulfill it.D&C 82:10 I, the Lord, am bound when ye do what I say; but when ye do not what I say, ye have no promise.
The way to guaranteed damnation: don't do, and teach others to not do, any one, some, or all, of the Lord's commandments in the Sermon on the Mount.
JST Matt 5:22 For I say unto you, except your righteousness shall exceed that of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.