So eat and drink and be contented. And if you see from among humanity anyone, say, 'Indeed, I have vowed to the Most Merciful abstention, so I will not speak today to [any] man.'"
(Who was below her) Meaning the one who was below her called to her. Others recited it as,
مِن تَحْتِهَآ
(from below her) With the meaning of a preposition (from) instead of a pronoun (who). The scholars of Tafsir have differed over the interpretation of who was calling out. Al-`Awfi and others reported from Ibn `Abbas that he said,
فَنَادَاهَا مِن تَحْتِهَآ
(Then cried unto her from below her,) "This is referring to Jibrilbecause `Isa did not speak until she brought him to her people." Similarly, Sa`id bin Jubayr, Ad-Dahhak, `Amr bin Maymun, As-Suddi and Qatadah all said, "Verily, this is referring to the angel Jibril." This means that he (Jibril) called out to her from the bottom of the valley. Mujahid said,
But in the matter of their actual use the order was reversed i.e. eating was enjoined first and then drinking. It is perhaps because normally a person first makes arrangement for drinking water and then for food, specially such food as is more likely to produce thirst. But when it comes to their use the sequence gets reversed i.e. one eats first and then drinks water. (Ruh ul-Ma ani).
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 26–27
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.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.