They quote their submission as a favour upon you; you say: "You shouldn’t quote your submission as a favour upon me, but Allah has favoured you by guiding you to the belief, if you are so Truthful!"
The Bedouin Arabs were showing their acceptance of Islam as a great favour upon Messenger Muhammad. The same approach is also seen among most of those who come to the class where it is taught what Islam is, what belief is, what the aim of life is, etc., in the heart's language. Actually, by attending the class where Adhikr is explained in a way that will penetrate their hearts like a hot iron rod, and by not following It and not reflecting It to others, they are causing to argue and witness against them what they heard from there, and are deserving themselves to be entered into Hell even without trial. See explanation 7: 43; 10: 7-8, 35-36; 39: 7-8 and 41-42.