Contradiction with Matthew 23:39
While Psalms 118:26 pronounces a blessing on those who come in the name of the Lord, Matthew 23:39 indicates that this blessing is withheld until a future acknowledgment of the Messiah's coming.
Matthew 23:39: For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed [is] he that cometh in the name of the Lord.
Contradiction with John 1:11
Psalms 118:26 talks about a blessing for the one who comes in the name of the Lord, but John 1:11 highlights the contradiction by showing that Jesus came to his own, and his own did not receive him.
John 1:11: He came unto his own, and his own received him not.
Contradiction with Luke 19:41-44
This passage in Luke shows Jesus weeping for Jerusalem, indicating that despite coming in the name of the Lord, they would face destruction, in contrast to the blessing mentioned in Psalms 118:26.
Luke 19:41-44: And when he was come near, he beheld the city, and wept over it,
Contradiction with Isaiah 53:3
Psalms 118:26 speaks of blessing, whereas Isaiah describes the coming one as despised and rejected, which contrasts with the blessing for the one who comes in the Lord's name.
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 Matthew 21:9
This verse supports Psalms 118:26, but the subsequent rejection and crucifixion of Jesus (despite this proclamation) present a contrasting outcome to the blessing mentioned.
Matthew 21:9: And the multitudes that went before, and that followed, cried, saying, Hosanna to the Son of David: Blessed [is] he that cometh in the name of the Lord; Hosanna in the highest.