Contradiction with Acts 1:8
While Matthew 17:9 instructs to keep the vision secret, Acts 1:8 commands the disciples to be witnesses "unto the uttermost part of the earth."
Acts 1:8: But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth. [power...: or, the power of the Holy Ghost coming upon you]
Contradiction with Mark 16:15
This verse directs followers to "preach the gospel to every creature," opposing the idea of keeping the transfiguration a secret as instructed in Matthew 17:9.
Mark 16:15: And he said unto them, Go ye into all the world, and preach the gospel to every creature.
Contradiction with Matthew 28:19
The Great Commission directs the disciples to "teach all nations," which contrasts the temporary secrecy urged in Matthew 17:9.
Matthew 28:19: Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: [teach...: or, make disciples, or, Christians of all nations]
Contradiction with Luke 12:3
This verse suggests that what is spoken or heard in secret should eventually be proclaimed openly, differing from the immediate secrecy in Matthew 17:9.
Luke 12:3: Therefore whatsoever ye have spoken in darkness shall be heard in the light; and that which ye have spoken in the ear in closets shall be proclaimed upon the housetops.
Contradiction with John 15:27
Here, Jesus tells his disciples that they shall bear witness because they have been with Him from the beginning, contrasting the secrecy of the transfiguration event mentioned in Matthew 17:9.
John 15:27: And ye also shall bear witness, because ye have been with me from the beginning.