Concerning Allah's statement,

وَاصْطَنَعْتُكَ لِنَفْسِي ﴿٤١﴾

And I have chosen you for Myself.

This means, "I have chosen you and selected you to be a Messenger for Myself. This is as I wish and according to My will.''

Concerning the Tafsir of this Ayah, Al-Bukhari recorded that Abu Hurayrah said that the Messenger of Allah said,

الْتَقَى آدَمُ وَمُوسَى فَقَالَ مُوسَى: أَنْتَ الَّذِي أَشْقَيْتَ النَّاسَ وَأَخْرَجْتَهُمْ مِنَ الْجَنَّةِ،

فَقَالَ آدَمُ: وَأَنْتَ الَّذِي اصْطَفَاكَ اللهُ بِرِسَالَتِهِ وَاصْطَفَاكَ لِنَفْسِهِ، وَأَنْزَلَ عَلَيْكَ التَّوْرَاةَ؟

قَالَ: نَعَمْ،

قَالَ: فَوَجَدْتَهُ مَكْتُوبًا عَلَيَّ قَبْلَ أَنْ يَخْلُقَنِي؟

قَالَ: نَعَمْ،

فَحَجَّ آدَمُ مُوسَى

Adam and Musa met, and Musa said, "You are the one who made things difficult for mankind and you caused them to be evicted from Paradise.''

Adam said, "Are you the one whom Allah chose for His Message, and He selected you for Himself and He revealed the Tawrah to you?''

Musa replied, "Yes.''

Then Adam said, "Did you find that it was preordained upon me before He (Allah) created me?''

Musa replied, "Yes.''

Therefore, Adam defeated Musa's argument.

Both Al-Bukhari and Muslim recorded this narration.