Tafsir of Al-Qasas 28:12

"And We had forbidden him [all] wet nurses" The "forbidding" (al-taḥrīm) is a metaphor for prevention (al-manʿ), for whoever is forbidden from something has been prevented from it. Do you not see their saying: "forbidden" (maḥẓūr) and "restricted" (ḥijr)? This is because God prevented him from suckling any breast; he would not accept the breast of any wet nurse at all, until this distressed them.

"Wet nurses" (al-marāḍiʿ) is the plural of murḍiʿ (a woman who breastfeeds), or it is the plural of marḍaʿ (the place of breastfeeding, meaning the breast or the act of nursing).

"Before" Meaning: before she traced his tracks (qaṣaṣahā atharahu). It is narrated that when she said, "And they are sincere to him," Haman said, "She surely knows him and knows his family." She replied, "I only meant they are sincere to the King." Sincerity (al-nuṣḥ) is the purification of an action from the impurities of corruption. She departed to her mother by their command, and she brought her [the mother]. The infant was in Pharaoh’s hands, and he was comforting him out of pity while he cried, seeking milk. When the infant smelled her scent, he became comforted and latched onto her breast. Pharaoh said to her, "Who are you to him? For he has refused every breast except yours?" She said, "I am a woman of pleasant scent and pleasant milk; no infant is brought to me but that he accepts me." So he handed him over to her and provided for her. She took him to her house, and God fulfilled His promise of returning him. At that moment, it was confirmed and established in her knowledge that he would be a prophet.

"And that she might know that the promise of God is true" Meaning: that her knowledge might be established and secured.

If you ask: How was it lawful for her to take a wage for nursing her own son? I say: She was not taking it as a wage for nursing, but rather it was wealth from the enemy (māl ḥarbī) which she took by way of permissibility.

"But most of them do not know" This falls under the scope of her knowledge. The meaning is: "That she might know that the promise of God is true, but most people do not know that it is true, so they doubt." It also resembles an allusion to what she had committed when she heard the news of Moses and became distraught, and her heart became empty. It is narrated that when she cast the chest into the river, Satan came to her and said, "O mother of Moses, you disliked that Pharaoh should kill Moses and you be rewarded, so you went and took charge of killing him yourself." When the news reached her that Pharaoh had found him, she said, "He has fallen into the hands of the enemy," and she forgot the promise of God.

It is also possible that "but" (wa-lākin) relates to His saying, "that she might know." Its meaning is: The return [of the child] was only for this religious purpose, which is her knowledge of the truthfulness of God’s promise. But most people do not know that this is the primary purpose, to which everything else—such as the coolness of her eyes and the departure of her grief—is merely secondary.

"And when he attained his maturity and became established, We gave him judgment and knowledge. And thus do We reward the doers of good."