This harsh phrase was uttered by Christ in the Gospel this weekend toward a Canaanite woman. You can find it here. It seems rather uncharacteristic from the same man who wouldn't carry out a death sentence for a woman who was caught committing adultery despite the clarity of the law. (Although it appears our evangelical brothers and sisters are trying to eliminate this passage from the gospel.)
I think that we miss a nuance. I believe Jesus was "playing along" to make a point: If Jesus disciples think that a Canaanite is not worthy of the Kingdom of Heaven, how are they going to deal with a Greek or a Gaulite? They need to see the universality of salvation and not be so exclusive. Jesus wants all people saved, not just the people we like.