Contradiction with Isaiah 53:3
This verse speaks of the Messiah as being despised and rejected by men, which contrasts with the multitude's adoration in Matthew 21:9.
Isaiah 53:3: He is despised and rejected of men; a man of sorrows, and acquainted with grief: and we hid as it were [our] faces from him; he was despised, and we esteemed him not. [we hid...: or, he hid as it were his face from us: Heb. as an hiding of faces from him, or, from us]
Contradiction with Luke 23:21
The people cry out for Jesus to be crucified, which contradicts the hosannas and praise he receives in Matthew 21:9.
Luke 23:21: But they cried, saying, Crucify [him], crucify him.
Contradiction with John 1:11
This verse states that Jesus came to his own, and his own did not receive him, conflicting with the reception he gets in Matthew 21:9.
John 1:11: He came unto his own, and his own received him not.
Contradiction with Mark 6:4
Jesus notes that a prophet is not without honor, except in his own country, which contradicts the honor he receives in Matthew 21:9.
Mark 6:4: But Jesus said unto them, A prophet is not without honour, but in his own country, and among his own kin, and in his own house.