Tafsir of Al-Ahzab 33:45

"O Prophet! Indeed, We have sent you as a witness" — over those to whom you were sent, observing their states, witnessing their deeds, bearing witness on their behalf regarding what proceeded from them—be it belief or denial, and all else they are upon of guidance or misguidance—and delivering that testimony on the Day of Resurrection in a manner that is accepted, regarding what is in their favor and what is against them. This [witnessing] is a future-oriented state (hal muqaddarah). If the sending (irsal) is considered an extended affair to account for the bearing and delivering of the testimony, then the sending—in that consideration—even if it is contemporaneous with the bearing of the testimony, is not contemporaneous with the delivering of it. If the extension is not considered at all, then all the states are future-oriented.

Furthermore, the bearing of testimony regarding those who lived contemporaneously with him (peace and blessings of Allah be upon him) and whose deeds he witnessed is a manifest matter. As for bearing testimony regarding those who came after him as specific individuals, if this is also intended, there is ambiguity in it, for the apparent meaning of the narrations is that he (peace and blessings of Allah be upon him) does not know the specific deeds of those who came after him. It is narrated by Abu Bakr, Anas, Hudhayfah, Samurah, and Abu al-Darda’ from him (peace and blessings of Allah be upon him): "People from my companions will be brought to the Hawd (cistern) until, when I see them and recognize them, they will be snatched away from me. I will say: 'O Lord, my companions! My companions!' And it will be said to me: 'You do not know what they innovated after you.'"

Yes, it may be said that he (peace and blessings of Allah be upon him) knows of the acts of obedience and disobedience that occur after him from his nation, but he does not know the specific identities of the obedient and the disobedient. By this, the aforementioned hadith and the hadith regarding the presenting of deeds to him (peace and blessings of Allah be upon him) every week, or more, or less, are reconciled. It has also been said that they are reconciled by suggesting he (peace and blessings of Allah be upon him) does know the individuals, but he forgot, and so he said "my companions," and to emphasize the ugliness of what they innovated, it was said to him: "You do not know what they innovated after you." It is also suggested that what is presented is everything except disbelief—and this is as you see it. As for the claim that the bearing of testimony extends to those who come after him until the Day of Resurrection because he (peace and blessings of Allah be upon him) is alive in spirit and body, traveling wherever he wills in the regions of the earth and the celestial realm, it is built upon what you know of its status, and perhaps these two narrations contain that which rejects it, as is not hidden from the contemplative.

Some of the Sufi masters have indicated that Allah the Almighty has granted him (peace and blessings of Allah be upon him) insight into the deeds of the servants, and so he looked upon them; for this reason, he (peace and blessings of Allah be upon him) was designated as a "Witness." Our master Jalal al-Din al-Rumi—may his secret be sanctified—said in his Mathnawi: “The stations of the servants were in his view; for that reason, God named him 'Witness.'” So contemplate and do not be heedless.

It is said: the meaning is a witness over all nations on the Day of Resurrection that their prophets had conveyed the message to them and called them to Allah the Almighty; his testimony to that is due to what he knew from His Glorious Book. It is also said: the meaning is a witness that there is no god but Allah.

"And a bringer of good tidings" — you give good tidings to the obedient of Paradise.

"And a warner" — you warn the disbelievers and the disobedient of the Fire. Due to the generality of warning and the specificity of good tidings, it is said that mubashshiran (bringer of good tidings) and nadhiran (warner) are in the form of intensive nouns (mubalagha), rather than [using] mundhiran (warning agent), even though the apparent structure of connecting it to mubashshiran necessitates that. Good tidings were placed first due to the nobility of those receiving them, and because it is the primary intent, as he (peace and blessings of Allah be upon him) is a mercy to the worlds. It is as if, for this reason, he compensated for what was missed of intensification by the saying of the Almighty: "And give good tidings to the believers."