Jesus challenged many old testament laws being enforced by the religious powers of that time. Perhaps the laws of Moses were being misinterpreted:

- An eye for an eye? Jesus said no, turn the other cheek.

- If your donkey falls in the well on a sabbath are you going to leave it there till the next day? Jesus didnt think you should.

- The story of the good Samaritan by Jesus is another sample. While the religious bypassed a stranger in need, the good Samaritan did not let religious doctrine get in the way of helping his fellow man.

-Also, the time when the high priests brought a sinful women to a crowd with Jesus, the high priest said that according to the laws of Moses she must be stoned, but Jesus replied "Let he who has no sin throw the first stone" and of course the crowd withered away. And Jesus did not condemn her but told her to "go and sin no more"

Of course Jesus did not reject everything, the apostles asked about the 10 commandments and Jesus told them to keep the 10 commandments. So the Old Testament has to be questioned when it contradicts with the teachings of Jesus.