Contradiction with Psalm 118:22
This verse is the source of the quote in Matthew 21:42, supporting rather than contradicting it.
Psalm 118:22: The stone [which] the builders refused is become the head [stone] of the corner.
According to Matthew, Jesus is saying that something important that people ignored has now become the most important thing of all, and this is something wonderful that God has done. It's like when a piece of LEGO everyone thought was useless turns out to be the special one that completes the building perfectly.
Matthew 21:42: Jesus saith unto them, Did ye never read in the scriptures, The stone which the builders rejected, the same is become the head of the corner: this is the Lord's doing, and it is marvellous in our eyes?
This verse is the source of the quote in Matthew 21:42, supporting rather than contradicting it.
Psalm 118:22: The stone [which] the builders refused is become the head [stone] of the corner.