How does Thomas respond to Douglass's request for protection?

From the text:

"Master Thomas ridiculed the idea that there was any danger of Mr. Covey’s killing me, and said that he knew Mr. Covey; that he was a good man, and that he could not think of taking me from him; that, should he do so, he would lose the whole year’s wages; that I belonged to Mr. Covey for one year, and that I must go back to him, come what might; and that I must not trouble him with any more stories, or that he would himself get hold of me."