Revelation 14:6 KJV
(6)  And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people.

Mark 16:15-16 ASV
(15)  And he [JESUS] said unto them, Go ye into all the world, and preach the gospel to the whole creation.
(16)  He that believeth and is baptized shall be saved; but he that disbelieveth shall be condemned.

Matthew 28:19-20 ASV
(19)  Go ye therefore, and make disciples of all the nations, baptizing them into the name of the Father and of the Son and of the Holy Spirit:
(20)  teaching them to observe all things whatsoever I commanded you: and lo, I am with you always, even unto the end of the world.

Deuteronomy 12:32 ASV
(32)  What thing soever I command you, that shall ye observe to do: thou shalt not add thereto, nor diminish from it.