How Musa asked for the Support of His Brother and was granted that by Allah
When Allah commanded him to go to Fir`awn, the one who he had run away from and whose vengeance he feared,
﴿ قَالَ رَبِّ إِنِّى قَتَلۡتُ مِنۡهُمۡ نَفۡسً۬ا ﴾
( Musa said: My Lord! I have killed a man among them,) meaning, that Coptic,
﴿ فَأَخَافُ أَن يَقۡتُلُونِ ﴾
(and I fear that they will kill me.) i.e., `when they see me.'
﴿ وَأَخِى هَـٰرُونُ هُوَ أَفۡصَحُ مِنِّى لِسَانً۬ا ﴾
(And my brother Harun -- he is more eloquent in speech than me,) Musa, (peace be upon him) had a speech defect, because when he had been given the choice between a date and a pearl, he mistakenly picked up a coal and placed it on his tongue, so he found it difficult to speak clearly. Musa said:
﴿ وَٱحۡلُلۡ عُقۡدَةً۬ مِّن لِّسَانِى • يَفۡقَهُواْ قَوۡلِى • وَٱجۡعَل لِّى وَزِيرً۬ا مِّنۡ أَهۡلِى • هَـٰرُونَ أَخِى • ٱشۡدُدۡ بِهِۦۤ أَزۡرِى • وَأَشۡرِكۡهُ فِىٓ أَمۡرِى ﴾
("And loose the knot (the defect) from my tongue. That they understand my speech. And appoint for me a helper from my family, Harun, my brother. Increase my strength with him, And let him share my task.'') (20:27-32) meaning, `give me someone to keep me company in this immense task of prophethood and conveying the Message to this arrogant, tyrannical and stubborn king. ' Hence Musa said:
﴿ وَأَخِى هَـٰرُونُ هُوَ أَفۡصَحُ مِنِّى لِسَانً۬ا فَأَرۡسِلۡهُ مَعِىَ رِدۡءً۬ا ﴾
(And my brother Harun -- he is more eloquent in speech than me: so send him with me as a helper) meaning, as a support to give strength to my cause and confirm what I say and convey from Allah, because the word of two carries more weight in people's minds than the word of one. So he said:
﴿ إِنِّىٓ أَخَافُ أَن يُكَذِّبُونِ ﴾
(Verily, I fear that they will deny me.) Muhammad bin Ishaq said:
﴿ رِدۡءً۬ا يُصَدِّقُنِىٓۖ ﴾
(as a helper to confirm me.) means, `to explain to them what I say, for he can understand me where they may not.' When Musa asked for this, Allah said to him:
﴿ سَنَشُدُّ عَضُدَكَ بِأَخِيكَ ﴾
(We will strengthen your arm through your brother,) meaning, `We will add strength to your cause and give you help through your brother, who you have asked to be made a Prophet alongside you.' This is like the Ayat;
﴿ قَدۡ أُوتِيتَ سُؤۡلَكَ يَـٰمُوسَىٰ ﴾
(You are granted your request, O Musa!) (20:36)
﴿ وَوَهَبۡنَا لَهُ ۥ مِن رَّحۡمَتِنَآ أَخَاهُ هَـٰرُونَ نَبِيًّ۬ا ﴾
(And We granted him his brother Harun, (also) a Prophet, out of Our mercy) (19:53). One of the Salaf said, "There is no one who has ever done a greater favor to his brother than Musa did for Harun, may peace be upon them both, for he interceded for him until Allah made him a Prophet and Messenger with him to Fir`awn and his chiefs. Allah said concerning Musa:
﴿ وَكَانَ عِندَ ٱللَّهِ وَجِيہً۬ا ﴾
(he was honorable before Allah) (33:69).
﴿ وَنَجۡعَلُ لَكُمَا سُلۡطَـٰنً۬ا ﴾
(and (We will) give you both power) means, overwhelming evidence.
﴿ فَلَا يَصِلُونَ إِلَيۡكُمَاۚ بِـَٔايَـٰتِنَآ ﴾
(so they shall not be able to harm you, with Our Ayat;) means, `they will have no way or means of harming you because you are conveying the signs of Allah.' This is like the Ayat:
﴿ يَـٰٓأَيُّہَا ٱلرَّسُولُ بَلِّغۡ مَآ أُنزِلَ إِلَيۡكَ مِن رَّبِّكَۖ ﴾
(O Messenger! Proclaim (the Message) which has been sent down to you from your Lord.) until His saying:
﴿ وَٱللَّهُ يَعۡصِمُكَ مِنَ ٱلنَّاسِۗ ﴾
(Allah will protect you from mankind) (5:67).
﴿ ٱلَّذِينَ يُبَلِّغُونَ رِسَـٰلَـٰتِ ٱللَّهِ ﴾
(Those who convey the Message of Allah) until His saying:
﴿ وَكَفَىٰ بِٱللَّهِ حَسِيبً۬ا ﴾
(And sufficient is Allah as a Reckoner) (33:39). And sufficient is Allah as a Helper and Supporter. And Allah told them the consequences in this world and the next, for them and for those who followed them,
﴿ أَنتُمَا وَمَنِ ٱتَّبَعَكُمَا ٱلۡغَـٰلِبُونَ ﴾
(you two as well as those who follow you will be the victors.) This is like the Ayat:
﴿ ڪَتَبَ ٱللَّهُ لَأَغۡلِبَنَّ أَنَا۟ وَرُسُلِىٓۚ إِنَّ ٱللَّهَ قَوِىٌّ عَزِيزٌ۬ ﴾
(Allah has decreed: "Verily, it is I and My Messengers who shall be the victorious.'' Verily, Allah is All-Powerful, All-Mighty.) (58:21)
﴿ إِنَّا لَنَنصُرُ رُسُلَنَا وَٱلَّذِينَ ءَامَنُواْ فِى ٱلۡحَيَوٰةِ ٱلدُّنۡيَا ﴾
(Verily, We will indeed make victorious Our Messengers and those who believe in this world's life) (40:51) to the end of the Ayah.
﴿ فَلَمَّا جَآءَهُم مُّوسَىٰ بِـَٔايَـٰتِنَا بَيِّنَـٰتٍ۬ قَالُواْ مَا هَـٰذَآ إِلَّا سِحۡرٌ۬ مُّفۡتَرً۬ى وَمَا سَمِعۡنَا بِهَـٰذَا فِىٓ ءَابَآٮِٕنَا ٱلۡأَوَّلِينَ • وَقَالَ مُوسَىٰ رَبِّىٓ أَعۡلَمُ بِمَن جَآءَ بِٱلۡهُدَىٰ مِنۡ عِندِهِۦ وَمَن تَكُونُ لَهُ ۥ عَـٰقِبَةُ ٱلدَّارِۖ إِنَّهُ ۥ لَا يُفۡلِحُ ٱلظَّـٰلِمُونَ ﴾
(36. Then when Musa came to them with Our Clear Ayat, they said: "This is nothing but invented magic. Never did we hear of this among our fathers of old.'') (37. Musa said: "My Lord knows best him who came with guidance from Him, and whose will be the happy end in the Hereafter. Verily, the wrongdoers will not be successful.'')