In The Name of Allah, The Most Merciful, The Bestower of Mercy.

Allah, The Most High, said:

وَأَوۡحَيۡنَآ إِلَىٰٓ أُمِّ مُوسَىٰٓ أَنۡ أَرۡضِعِيهِ‌ۖ فَإِذَا خِفۡتِ عَلَيۡهِ فَأَلۡقِيهِ فِى ٱلۡيَمِّ وَلَا تَخَافِى وَلَا تَحۡزَنِىٓ‌ۖ إِنَّا رَآدُّوهُ إِلَيۡكِ وَجَاعِلُوهُ مِنَ ٱلۡمُرۡسَلِينَ

فَٱلۡتَقَطَهُ ۥۤ ءَالُ فِرۡعَوۡنَ لِيَڪُونَ لَهُمۡ عَدُوًّ۬ا وَحَزَنًا‌ۗ إِنَّ فِرۡعَوۡنَ وَهَـٰمَـٰنَ وَجُنُودَهُمَا ڪَانُواْ خَـٰطِـِٔينَ

‘And We inspired the mother of Musa (Moses), (saying): “Suckle him [Musa (Moses)], but when you fear for him, then cast him into the river and fear not, nor grieve. Verily! We shall bring him back to you, and shall make him one of (Our) Messengers. Then the household of Fir’aun (Pharaoh) picked him up, that he might become for them an enemy and a (cause of) grief. Verily! Fir’aun (Pharaoh), Haman and their hosts were sinners.” [Al-Qasas 7-8]

Meaning: The end result and final outcome after they adopted Musa, peace and blessings of Allah be upon him, is that he will be an enemy of theirs and a cause of grief (for) them. This is because what they feared [i.e. that they were to be destroyed at the hands of a man from Bani Israa’eel] did not benefit them, for Allah already decreed it. And the one they feared amongst Bani Israa’eel had been destined to be a leader of theirs, who was to be nurtured by them, under their eyes and guardianship.

إِنَّ فِرۡعَوۡنَ وَهَـٰمَـٰنَ وَجُنُودَهُمَا ڪَانُواْ خَـٰطِـِٔين

Verily! Fir’aun (Pharaoh), Haman and their hosts were sinners.

Thus, Allah wished to punish them for their sins- planned for them a recompense for their plots and plans.

An Excerpt from  Tayseer Al-Kareem Ar-Rahmaan Fee Tafseer Kalaam al-Mannaan. Slightly paraphrased.