[It is] a revelation from the Lord of the worlds. (69:43)

Almuntakhab Fi Tafsir Alquran Alkarim

It -the utterance- is that of sacred words revealed by Allah, the Creator of the worlds, past present and those to come

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(69:43) It has been revealed by the Lord of the Universe. *24

[It is] a revelation from the Lord of the worlds. meaning

*24) In short: "I swear by whatever you see and by whatever you do not see that this Qur'an is not the word of a poet or a soothsayer, but it is a Revelation from the Lord of the worlds, which is being presented by the Messenger who is noble and gentle." Let us now consider in what sense this oath has been sworn. That which was visible to the people was:.
(1) This Word was being presented by a person who being noble and gentle was not hidden from anybody in the society of Makkah. Everyone knew that he was the best man of their nation in conduct. It could not be expected of such a man that he would forge a lie and attribute it to Allah, Lord of the worlds.
(2) They also saw clearly that he had no selfish motive in presenting that word before the people, but had rather sacrificed all His personal interests to it: had ruined his business, had abandoned every ease and comfort, was being cursed and abused by the same people who had shown him the highest veneration and esteem and had caused even his family and children to be subjected to these agonies besides himself. A person having selfish motives could not have submitted himself to such tribulations.
(3) They could also see that the lives of the people in their own society, who believed in him, underwent a sudden transformation. The word of no poet or soothsayer has been known to have brought about such a wonderful moral change in the people that his follower should become ready to face every hardship and bear up against every persecution for his sake.
(4) They were also not unaware of the language of poetry and the diction of the soothsayers. Apart from stubborn disbelievers, no one could say that the language of the Qur'an was the language of poetry or sorcery. (For a detailed discussion of this, see E.N. 7 of AI-Anbiya', E.N.'s 142-145 of Ash-Shu`ara', E.N.22 of At-Tur).
(5) This also was before their eyes that no one in entire Arabia was so eloquent of speech that his word could be brought to match with the Qur'an. Not to speak of equalling it, not even the greatest poet's eloquence could even approach anywhere near the Qur'an's.
(6) This also was not hidden from them that the language used by Muhanunad (upon whom be Allah's peace and blessings) himself was very different in its literary beauty and merit from the language of the Qur'an. No Arabic speaking person could, after hearing the Holy Prophet's own speech, and the Qur'an, say that both emanated from one and the same person.
(7) The people of Makkah had never heard even until a day before Muhammad (upon whom be Allah's peace and blessings) made the claim to Prophethood anything relating to the themes that the Qur'an consisted of, nor they knew that he had any means of obtaining that knowledge and information. That is why even if his opponents alleged that he obtained that information secretly from somewhere, no one in Makkah was prepared to believe it. (For explanatation, see E.N l07 of An-Nahl and E.N. 12 of AI-Furgan).
(8) They could also see the wonderful workshop of existence, from the earth to the heavens, which was functioning before their eyes, and in which they could see a supreme, wise law and, an all-pervading order and system at work. In it they could see no sign and evidence of the polytheism and denial of the Hereafter, which the Arabs had adopted as their creed, but there were signs and proofs of the existence of One God and of the truth of the Hereafter which the Qur'an was presenting.
All this they could see, and what they did not see was: Allah Almighty alone is the Creator and Master and Ruler of this universe: all others are only creatures: none beside Him is God! Resurrection has to take place inevitably; Muhammad (upon whom be Allah's peace and blessings) has really been appointed a Messenger by Allah Himself Who is sending down the Qur'an to him. An oath has been sworn by both truths to affirm that which has been stated in the preceding verses.
 

[It is] a revelation from the Lord of the worlds. meaning in Urdu

یہ رب العالمین کی طرف سے نازل ہوا ہے