Why did the Prophet, peace be upon him, command the burning of two people then retract his command, and does that contradict his infallibility and the Almighty’s saying: "Nor does he speak of (his own) desire"?

The Prophet, may Allah’s prayers and peace be upon him, ordered two men to be burned, then he abrogated that order, because none punishes with fire except Allah. This illustrates the principle of abrogation in the Sunnah, and the permissibility of abrogating a ruling before it is acted upon. It also warns against exposing oneself to doubts with little knowledge.