Question: How many angels were talking to Mary? When the Qur'an speaks about the annunciation of the birth of Jesus to the virgin Mary, Sura 3:42,45 speaks about (several) angels while it is only one in Sura 19:17-21.
3:42 Behold! the angels said: "O Mary! Allah hath chosen thee and purified thee- chosen thee above the women of all nations.
وَإِذْ قَالَتِ الْمَلاَئِكَةُ يَا مَرْيَمُ إِنَّ اللّهَ اصْطَفَاكِ وَطَهَّرَكِ وَاصْطَفَاكِ عَلَى نِسَاء الْعَالَمِينَ
3:43 "O Mary! worship Thy Lord devoutly: Prostrate thyself, and bow down (in prayer) with those who bow down."
يَا مَرْيَمُ اقْنُتِي لِرَبِّكِ وَاسْجُدِي وَارْكَعِي مَعَ الرَّاكِعِينَ
3:44 This is part of the tidings of the things unseen, which We reveal unto thee (O Messenger.) by inspiration: Thou wast not with them when they cast lots with arrows, as to which of them should be charged with the care of Mary: Nor wast thou with them when they disputed (the point).
ذَلِكَ مِنْ أَنبَاء الْغَيْبِ نُوحِيهِ إِلَيكَ وَمَا كُنتَ لَدَيْهِمْ إِذْ يُلْقُون أَقْلاَمَهُمْ أَيُّهُمْ يَكْفُلُ مَرْيَمَ وَمَا كُنتَ لَدَيْهِمْ إِذْ يَخْتَصِمُونَ
3:45 Behold! the angels said: "O Mary! Allah giveth thee glad tidings of a Word from Him: his name will be Christ Jesus, the son of Mary, held in honour in this world and the Hereafter and of (the company of) those nearest to Allah.
إِذْ قَالَتِ الْمَلآئِكَةُ يَا مَرْيَمُ إِنَّ اللّهَ يُبَشِّرُكِ بِكَلِمَةٍ مِّنْهُ اسْمُهُ الْمَسِيحُ عِيسَى ابْنُ مَرْيَمَ وَجِيهًا فِي الدُّنْيَا وَالآخِرَةِ وَمِنَ الْمُقَرَّبِينَ
3:46 "He shall speak to the people in childhood and in maturity. And he shall be (of the company) of the righteous."
وَيُكَلِّمُ النَّاسَ فِي الْمَهْدِ وَكَهْلاً وَمِنَ الصَّالِحِينَ
3:47 She said: "O my Lord! How shall I have a son when no man hath touched me?" He said: "Even so: Allah createth what He willeth: When He hath decreed a plan, He but saith to it, 'Be,' and it is! Topics discussed in this Verse:
قَالَتْ رَبِّ أَنَّى يَكُونُ لِي وَلَدٌ وَلَمْ يَمْسَسْنِي بَشَرٌ قَالَ كَذَلِكِ اللّهُ يَخْلُقُ مَا يَشَاء إِذَا قَضَى أَمْرًا فَإِنَّمَا يَقُولُ لَهُ كُن فَيَكُونُ
19:17 She placed a screen (to screen herself) from them; then We sent her our angel, and he appeared before her as a man in all respects.
فَاتَّخَذَتْ مِن دُونِهِمْ حِجَابًا فَأَرْسَلْنَا إِلَيْهَا رُوحَنَا فَتَمَثَّلَ لَهَا بَشَرًا سَوِيًّا
19:18 She said: "I seek refuge from thee to ((Allah)) Most Gracious: (come not near) if thou dost fear Allah." قَالَتْ إِنِّي أَعُوذُ بِالرَّحْمَن مِنكَ إِن كُنتَ تَقِيًّا
19:19 He said: "Nay, I am only a messenger from thy Lord, (to announce) to thee the gift of a holy son. قَالَ إِنَّمَا أَنَا رَسُولُ رَبِّكِ لِأَهَبَ لَكِ غُلَامًا زَكِيًّا
19:20 She said: "How shall I have a son, seeing that no man has touched me, and I am not unchaste?"
قَالَتْ أَنَّى يَكُونُ لِي غُلَامٌ وَلَمْ يَمْسَسْنِي بَشَرٌ وَلَمْ أَكُ بَغِيًّا
19:21 He said: "So (it will be): Thy Lord saith, 'that is easy for Me: and (We wish) to appoint him as a Sign unto men and a Mercy from Us':It is a matter (so) decreed."
قَالَ كَذَلِكِ قَالَ رَبُّكِ هُوَ عَلَيَّ هَيِّنٌ وَلِنَجْعَلَهُ آيَةً لِلنَّاسِ وَرَحْمَةً مِّنَّا وَكَانَ أَمْرًا مَّقْضِيًّا
My Answer: Two different timings, the first when the angels gave her the glad tidings of the Messiah while the second when one angel came to thee the gift of a holy son (at the actual timing of the formation of Jesus Christ himself in her womb).