Tafsir of Az-Zumar 39:39

{On your position} Meaning: Upon the state you are currently in, and your established course of hostility which you have firmly entrenched yourselves in. "Makāna" (position) is in the sense of "makān" (place); it is used metaphorically for an abstract state, just as "huna" (here) is used for time, and "haythu" (where) is used for place.

If you ask: "The proper phrasing would be 'I am acting upon my position,' so why was it omitted?" I say: For brevity, and for the added sense of warning it conveys. It signals that his (the Prophet's) state is not stagnant; rather, it increases in strength and intensity every day, because Allah is his Supporter, his Helper, and the One who will make his religion prevail over all others.

Do you not see in His saying: {You will come to know who will be visited by...} how He threatens them with his victory over them, and his dominance in this world and the Hereafter? For when disgrace and torment come to them, that is his honor and victory. Victory is perfected for him through the honor of those who are dear among his allies, and the humiliation of those who are base among his enemies.

{Disgracing him} This is a description of the torment, meaning: a torment that disgraces him. This refers to (the Battle of) Badr, and the everlasting torment, which is the torment of the Fire. It has also been recited as "makānātikum" (plural).

{Indeed, We have sent down to you the Book for the people in truth. So whoever is guided, it is for his own soul, and whoever goes astray, he only goes astray against it. And you are not a guardian over them.}