He said, "Thus [it will be]; your Lord says, 'It is easy (19:21)

Almuntakhab Fi Tafsir Alquran Alkarim

So be it, Thus said Allah, your Creator, this is an easy act actuated upon My Will and We will make him a symbol of Our Omnipotence denoting to the people Our Uniqueness and infinite power to say to any entity Be, and it is. He is a mercy from Us to guide the people into all truth, and for the matter of that it has already been decreed

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

(19:21) The angel replied, "So shall it be. Your Lord says, `This is an easy thing for Me to do, and We will do so in order to make that boy a Sign for the people *15 and a blessing from Us, and this must happen."

He said, "Thus [it will be]; your Lord says, 'It is easy meaning

*15) The word "So shall it be" are very significant as has been stated in E.N. 6. The plain meaning is this: "A pure son shall be born to you just as your Lord has decreed, even though no man has touched you. " The same was the response to prophet Zachariah as stated in v. 9 above. And it is a sheer perversion to interpret it as: "So shall it be that a man will touch you and a son will be born to you." For, if it were to mean: "You will bear a son like all other women of the world," the subsequent two sentences: "Your Lord says, 'This is an easy thing for Me to do, and We will make that boy a Sign for the people'," would have become meaningless: Had this birth been an ordinary birth like the birth of every other child, there would have been no occasion to boast: "It is an easy thing, and that it will be made a Sign (miracle). This will be so because the child will speak in the cradle. "
 

He said, "Thus [it will be]; your Lord says, 'It is easy meaning in Urdu

فرشتے نے کہا "ایسا ہی ہوگا، تیرا رب فرماتا ہے کہ ایسا کرنا میرے لیے بہت آسان ہے اور ہم یہ اس لیے کریں گے کہ اُس لڑکے کو لوگوں کے لیے ایک نشانی بنائیں اور اپنی طرف سے ایک رحمت اور یہ کام ہو کر رہنا ہے"