Tafsir of Al-Qasas 28:13

فرددناه إلى أمه كي تقر عينها

So We restored him to his mother, that her eye might be comforted, means, by him,

وﻻ تحزن

and that she might not grieve, (means, for him).

ولتعلم أن وعد الله حق

and that she might know that the promise of Allah is true. meaning, `We had promised her to return him to her and to make him one of the Messengers.' When he was returned to her, she realized that he was one of the Messengers, so as she brought him up, she treated him both as a child (with kindness) and as a Messenger (with respect).

ولكن أكثرهم ﻻ يعلمون

But most of them know not. means, they do not know the wisdom of Allah in His actions and their good consequences, for which He is to be praised in this world and the Hereafter. For a thing may happen that people do not like, but its consequences are good, as Allah says:

وعسى أن تكرهوا شييا وهو خير لكم وعسى أن تحبوا شييا وهو شر لكم

and it may be that you dislike a thing which is good for you and that you like a thing which is bad for you. (2:216)

فعسى أن تكرهوا شييا ويجعل الله فيه خيرا كثيرا

it may be that you dislike a thing and Allah brings through it a great deal of good. (4:19)