Joseph Smith said: The Lord once told me that what I asked for I should have. I have been afraid to ask God to kill my enemies, lest some of them should, peradventure, repent.
That is interesting. It should be compared to the long JST at the end of Genesis 14, as well as to these verses from the Book of Mormon.
Helaman 10:4 Blessed art thou, Nephi, for those things which thou hast done; for I have beheld how thou hast with unwearyingness declared the word, which I have given unto thee, unto this people. And thou hast not feared them, and hast not sought thine own life, but hast sought my will, and to keep my commandments.
5 And now, because thou hast done this with such unwearyingness, behold, I will bless thee forever; and I will make thee mighty in word and in deed, in faith and in works; yea, even that all things shall be done unto thee according to thy word, for thou shalt not ask that which is contrary to my will.
6 Behold, thou art Nephi, and I am God. Behold, I declare it unto thee in the presence of mine angels, that ye shall have power over this people, and shall smite the earth with famine, and with pestilence, and destruction, according to the wickedness of this people.
7 Behold, I give unto you power, that whatsoever ye shall seal on earth shall be sealed in heaven; and whatsoever ye shall loose on earth shall be loosed in heaven; and thus shall ye have power among this people.
8 And thus, if ye shall say unto this temple it shall be rent in twain, it shall be done.
9 And if ye shall say unto this mountain, Be thou cast down and become smooth, it shall be done.
10 And behold, if ye shall say that God shall smite this people, it shall come to pass.
11 And now behold, I command you, that ye shall go and declare unto this people, that thus saith the Lord God, who is the Almighty: Except ye repent ye shall be smitten, even unto destruction.