Interpretation of why the Boy was killed

Ibn `Abbas narrated from Ubayy bin Ka`b that the Prophet said:

«الْغُلَامُ الَّذِي قَتَلَهُ الْخَضِرُ طُبِعَ يَوْمَ طُبِعَ كَافِرًا»

In verse 81, it was said: فَأَرَ‌دْنَا أَن يُبْدِلَهُمَا رَ‌بُّهُمَا خَيْرً‌ا مِّنْهُ زَكَاةً وَأَقْرَ‌بَ رُ‌حْمًا " We, therefore, wished that their Lord would replace him with someone better than him in piety [ having good deeds and morals ] and more akin to affection [ fulfilling due rights of the parents ]."

It will be noticed that the form used in this situation is plural: خَشِينَا (we apprehended) and: أَرَ‌دْنَا (we wished). One reason for it could be that al Khadir (علیہ السلام) attributed this apprehension and wish to himself and to Allah Ta` ala both. And it is also possible that he may have attributed it to himself alone - if so, the expression: أَرَ‌دْنَا (we wished) would mean: 'we prayed to Allah' because this matter of replacing a boy with a better one is an act which falls in the exclusive domain of Allah Ta` ala. Al-Khadir (علیہ السلام) or some other human being cannot be associated with it.