فَنَادَىٰهَا مِن تَحْتِهَآ أَلَّا تَحْزَنِى قَدْ جَعَلَ رَبُّكِ تَحْتَكِ سَرِيًّا

In such difficult and trying circumstances, Mary could have had only one source of consolation, and that was that God’s angel should appear and reassure her; and that is exactly what happened. At that very movement, an angel came and told her to have no fear and said that whatever was taking place was in accordance with God’s plan. She was told that a spring of fresh water had been made to flow nearby, from which she might drink and that the palm tree would supply her with fresh fruits, which she might eat. As far as the child was concerned, the angel comforted her by saying that the miraculously born child was himself sufficient to defend her. She was advised to take a vow of strict silence as was customary among the Children of Israel. If anyone approached her and made enquiries, she was advised to point to the child, who would himself give a reply and absolve her of any responsibility.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (19:24)