[Pooya/Ali Commentary 94:2] In his prayer mentioned in the commentary of verse 1, Musa asked Allah to make his task easy and strengthen his back by appointing his brother Harun as his supporter for preaching the message of Allah. In the commentary of verses 9 to 98 of Ta Ha it has been mentioned with authentic references from well known Muslim scholars that the Holy Prophet also asked Allah to appoint Ali as his supporter and vicegerent. Refer to the event of dawat dhil ashirah in the commentary of Ali Imran: 52 and 53. For vizr (the "burden or weight" of prophethood) see commentary of Muzzammil: 5. So Ali ibn abi Talib was appointed by Allah as the bearer of the burden, announced by the Holy Prophet in dawat dhil ashirah and at Ghadir Khum (see commentary of Ma-idah: 67). To appoint Ali as his successor has been commanded by Allah in verse 7 of this surah.