Why did Jesus refer to Gentiles as dogs? The passage below raises two questions in my mind but I suspect they both have the same answer. My questions are:

Why did Jesus at first refuse to speak to the Canaanite woman? We know He had no problem crossing gender and racial barriers, as seen e.g. in The Woman at the Well (John 4:1-42).
Why did He refer to her (and presumably all Canaanites and probably all Gentiles) as &quot;dogs&quot;? I say that He was referring to all Gentiles because He contrasted helping her with Israel, when He said, &quot;I was sent only to the lost sheep of Israel.&quot;


Matthew 15:21-28
Leaving that place, Jesus withdrew to the region of Tyre and Sidon. A Canaanite woman from that vicinity came to him, crying out, “Lord, Son of David, have mercy on me! My daughter is suffering terribly from demon-possession.”
Jesus did not answer a word. So his disciples came to him and urged him, “Send her away, for she keeps crying out after us.”
He answered, “I was sent only to the lost sheep of Israel.”
The woman came and knelt before him. “Lord, help me!” she said.
He replied, “It is not right to take the children’s bread and toss it to their dogs.”
“Yes, Lord,” she said, “but even the dogs eat the crumbs that fall from their masters’ table.”
Then Jesus answered, “Woman, you have great faith! Your request is granted.” And her daughter was healed from that very hour.

(This story is also related in Mark 7:24-30.)
Jesus is the king of metaphors. This reference was not meant as an insult. 

To quote from Life Application Study Bible in reference to Matthew 15:24:


  Jesus' words do not contradict the truth that God's message is for all people. After all, when Jesus said these words, He was in Gentile territory on a mission to Gentile people. He ministered to Gentiles on many other occasions also. Jesus was simply telling the woman that Jews were to have the first opportunity to accept Him as the Messiah because God wanted them to present the message of salvation to the rest of the world. Jesus was not rejecting the Gentile woman. He may have wanted to test her faith, or He may have wanted to use the situation as another opportunity to teach that faith is available to all people.


Had she taken what He said as an insult, as it may sound to us today, her faith would have been damaged and her daughter would not have been healed. It is obvious that she understood His reference as nothing more than a metaphor. Much the same as we are referred to as sheep.