The Speech of Allah:
The fact that Allah spoke directly to the Prophet Musa (علیہ السلام) is confirmed by the Qur'an in clear terms. The first time Allah spoke with the Prophet Musa (علیہ السلام) was when he was entrusted with Prophethood. This is the second time at the occasion of giving him the Torah that He spoke to him. The wording of the present verse indicates that this later discourse of Allah had some additional characteristics as compared to the first speech of Allah.
As to the question what was the nature and character of this discourse, cannot be ascertained by anyone but Allah. Only those logical suppositions, in this regard, can be allowed which do not go against any rule of the Shari` ah. None of such views can be accepted as being definite unless supported by some valid argument. The best practice, in this regard, is the one followed by the Companions, their disciples, and the elders who followed them. They left such matters to Allah and never tried to make ungrounded supposition to resolve them. (Bayan al-Qur'an).