(As Handed On To Me by James A. Nestingen)
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. (Matthew 15:21-28)
She had obviously heard about Jesus previously, maybe even from off-handed comments or even rumors. Her daughter was sick so she sought the gossiped-about Jesus as he was leaving for Tyre and Sidon. Martin Luther comments of her that, "the woman is not vexed with doubts as to her privilege of coming to Christ: she does not spend the time in debating the question, whether she dare come or not; she simply starts upon her way and comes.”  Needless to say, she in all likelihood had not prepared herself, for the rude manner in which he treated her. Luther surmises that rather than putting her off, Christ was in fact pursuing faith in her like the "hunter, driving up a pheasant in the field."
Luther claims that Christ, knowing her faith is playing with her, goes right for the kill spot, right for the jugular. He is not polite; he ignores her and tells her that he literally has not come for her. Yet she knows because she has already heard the Word in regard to Him, that without Him there is no hope.
To our way of thinking, Christ should have demanded of her a polite request, and she should have found any answer He gave sufficient. He is God after all. But the Word had worked faith in her; it explodes faith and demands results. (Rm. 1:16; 10:17) Says Luther: "Just here we notice the beauty and excellence of this example; for we learn from it the mighty strength of faith. Faith takes hold of Christ's words, even when they sound harshly, and changes them into soothing expressions of consolation.” 
But what happens? This woman has been brought to faith on the basis of what she has heard from gossip and mere rumors about Jesus, the Christ. She literally has nothing more to go on. And what happens? She tries to get his attention and gets nothing but rudeness as a reply.
Next she began to draw more attention to herself with the disciples and to them demands that the God of all the universe listen to her, stop toying with her, and do what He has promised to do; bring healing and peace. She pesters the disciples until finally they are beyond annoyed with this demanding alien and heathen, and they go to Jesus and say, "Send her away, for she keeps crying out after us." Jesus says to her, "it is not right to take what belongs to the children and give it to the dogs."
Yet she knows who He is and what the gossips say He has done. The Word, even through irreverent gossip, has begun to take a hold of her. "Yes, Lord. Even dogs eat the crumbs that fall from the master’s table or from the children’s table." On the demand that He stop toying with her, that faith based on rumor ought not abide, but rather that He do as He has promised, He responds, "Oh woman, great is your faith. Great is your faith." The Christ does it; he capitulates to her insolent demands of Him. She endured His harsh treatment of her and just as Jacob had done (Genesis 32:1-33), she wrestled the blessing right out of His hands, and now He rejoices with her.
This is the power that we ought to demand from the Word in conversion. If we believe that the Word is the “means of grace,” then we believe it has power. The Word has this power when it gets loose and it ravishes until peace, the peace that surpasses all understanding, rests on the sinner.  As Luther himself concludes his sermon: "He will be merciful and ready to help us if we but come unto Him with our sorrows, and trust in Him with a believing heart.”