Does this idiom of Matthew 7:6 remind you of some place?

These are the words of Jesus pbuh when we went to another land, and the lady said "Oh my son is in ever need of help, he has befolen a disease, cure him please" Jesus pbuh said "It is not of me to take the bread of one people "People of Judea - his mission" and throw it to the dogs "Another people - where his mission is not".