Some verses that say otherwise:
Gen 12:3 And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed.
Num 22:12 And God said unto Balaam, Thou shalt not go with them; thou shalt not curse the people: for they are blessed.
Num 23:8 How shall I curse, whom God hath not cursed? or how shall I defy, whom the LORD hath not defied?
Deu 11:26 Behold, I set before you this day a blessing and a curse;
Deu 11:27 A blessing, if ye obey the commandments of the LORD your God, which I command you this day:
Deu 11:28 And a curse, if ye will not obey the commandments of the LORD your God, but turn aside out of the way which I command you this day, to go after other gods, which ye have not known.
Job 31:30 Neither have I suffered my mouth to sin by wishing a curse to his soul.
Mat 5:44 But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you;
Luk 6:28 Bless them that curse you, and pray for them which despitefully use you.
Rom 12:14 Bless them which persecute you: bless, and curse not.
Gal 3:10 For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.
Jam 3:8 But the tongue can no man tame; it is an unruly evil, full of deadly poison.
Jam 3:9 Therewith bless we God, even the Father; and therewith curse we men, which are made after the similitude of God.
Jam 3:10 Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be.
Mat 5:39 But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Joh 13:34 A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another.
2Ti 3:16 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: