Again the high priest asked him, and said to him: Art thou the Christ the Son of the blessed God? And Jesus said to him: I am. And you shall see the Son of man sitting on the right hand of the power of God, and coming with the clouds of heaven. (Mark 14:61-62)
That is incorrect. Nowhere in the law is it a violation for the TRUE Messiah to claim to be the Son of God. Messianic prophecy already was written that He would be "God with us".