Tafsir of Al-Anbiya' 21:109

(Then if they turn away) from Islam and pay no heed to what it necessitates, (then say) to them:

(I have announced to you) meaning: I have made known to you that which I have been commanded, or [I have announced] my war against you. Al-idhān is the form IV verb from al-idhn (permission); its root meaning is knowledge regarding the authorization and licensing of a thing. It was then used metaphorically for absolute knowledge, from which this verb form was derived. It frequently implies the meaning of warning and admonition, and it takes two objects, the second of which is implied, as has been indicated.

The saying of the Exalted (on an equal basis) is in the position of a state (ḥāl) for the first object; meaning, you are all equal in my notifying you of this, for I have not singled out one of you over another. It has been permitted that it could be in the position of a state for both the subject and the object simultaneously; meaning, I and you are on equal footing regarding the hostility, or equal in the knowledge of what I have notified you of—namely, the oneness of Allah, the Exalted—due to the existence of evidence for it. It has been said: What the Prophet (may Allah bless him and grant him peace) notified them of, it is possible that it refers to that [the oneness of God], or it could refer to the occurrence of war between us, and their equality in the knowledge of that comes from his notifying them of it, even though they know that he (upon him be peace and prayer) is the Truthful, the Trustworthy, despite their stubborn denial of some of what he informs them of. So reflect upon this.

It is also permitted that the prepositional phrase (jār wa majrūr) is in the position of an adjective for an implied verbal noun; that is, "an announcement on an equal basis." Or, that it is in the position of a predicate for an implied anna; meaning, "I have notified you that I am on an equal basis," i.e., [upon] justice and uprightness of opinion through luminous proof. However, this is quite contrary to what is immediately obvious.

In al-Kashshāf, it is stated that the saying of the Exalted (I have announced to you)... etc., is a metaphorical representation (isti'ārah tamthīliyyah). He likens himself to one who has a truce between him and his enemies, but senses their treachery, so he casts the treaty back to them, makes that rejection public, broadcasts it, and notifies them all of it. It is of excellent quality.

(And I do not know) meaning: I do not know (whether it is near or far, that which you are promised) of the Muslims' victory over you, the appearance of the religion, or the Gathering—despite it being inevitable. The sentence is in the accusative position due to adrī (I know). The structure "is that which you are promised near or far" was not used here in order to observe the rhythm of the verse endings.