John Calvin on Matthew 15:25

25. And she came and worshipped him. We might be apt to think that this woman contends with some measure of obstinacy, as if she would extort something from Christ in spite of him; but there is no reason to doubt that she was animated by the conviction which she entertained as to the kindness of the Messiah. When Christ expressly declared that it did not belong to his office, she was not intimidated by that refusal, and did not desist from her purpose. The reason was, that she adhered firmly to that previous sentiment of faith which I have mentioned, and admitted nothing that was opposed to her hope. And this is the sure test of faith, that we do not suffer that general commencement of our salvation, which is founded on the word of God, to be in any way torn from us.