The Angel will bear Witness; Allah commands that the Disbeliever be thrown into the Fire
Allah the Exalted states that the scribe angel, who is entrusted with recording the deeds of mankind, will testify against him or her about the deeds he or she did on the Day of Resurrection. He will say,
هَـذَا مَا لَدَىَّ عَتِيدٌ
("Here is (his record) ready with me!"), here it is prepared and completed without addition or deletion. This is when Allah the Exalted will judge the creation with fairness, saying,
أَلْقِيَا فِى جَهَنَّمَ كُلَّ كَفَّارٍ عَنِيدٍ
(Both of you throw into Hell every stubborn disbeliever.) It appears that Allah will say these words to the Sa'iq and Shahid angels; the Sa'iq drove him to the grounds where Reckoning is held and the Shahid testified. Allah the Exalted will order them to throw him in the fire of Jahannam, and worse it is as a destination,
قَالَ قَرِينُهُ رَبَّنَا مَا أَطْغَيْتُهُ (His (evil) companion (i.e. the Shaitan) will say, "0 our Lord, I did not cause him to rebel,...50:27). The word qarin literally denotes a companion, that is, one who accompanies or associates with another. From this point of view, qarin in the preceding verse referred to the two angels that accompany human beings and record their deeds. Just as there are two angels in the company of man, there is a devil entrusted to every man, who calls him towards commission of sins, and thus leads him astray. In this verse qarin refers to that devil. When it will be ordered that the person be thrown into Hell, it seems that he will say that the devil had led him astray, otherwise he would have done righteous deeds. In response, the devil will disown him and say about the human who came on the Day of Resurrection as an unbeliever that "I did not lead him astray. In fact he himself was misguided, paying no heed to the truth". In response Allah will say what follows in the next verse.
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 18–28
The study of this world shows that there is an unerring system of ‘recording’ in operation here. Man’s thoughts are impressed on the membrane of his brain. Every utterance a man makes is permanently preserved in the shape of sound waves in the air. Man’s actions are preserved in the external world by means of heat waves in such a way that they can be repeated at any time. All these are known facts of today, and these known facts are what make the Quran’s claim credible that man’s intentions, his utterances and his actions, are all in the knowledge of his Creator. All affairs of all human beings are entered in the registers of the angels.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.