Tafsir of Maryam 19:44

For indeed, he is the one who inspires you to do so and incites you towards it.

His statement: "Indeed, Satan has ever been, to the Most Merciful, disobedient," is an explanation for the necessity of the prohibition and a confirmation of it, by clarifying that he is rebellious against the One whose mercy has encompassed you and whose blessings have enveloped you. There is no doubt that he who obeys a disobedient one is himself disobedient, and everyone who is disobedient is deserving of having blessings withdrawn from him and being subjected to retribution.

The name "The Most Merciful" (Al-Rahman) was used to point towards this meaning. It also contains an indication of the absolute hideousness of his disobedience. The reason for limiting the mention to his "disobedience" among all his other crimes is that it is the foundation of them all, or because it is the result of his enmity towards Adam—upon him be peace—and thus, reminding [the father] of it is an incentive for him to avoid befriending or obeying him. Using the noun (Satan) in place of a pronoun (e.g., "he") is to provide further emphasis.