Jamieson, Fausset and Brown on Exodus 3:6-8

6-8. I am the God ... come down to deliver--The reverential awe of Moses must have been relieved by the divine Speaker (see Mt 22:32), announcing Himself in His covenant character, and by the welcome intelligence communicated. Moreover, the time, as well as all the circumstances of this miraculous appearance, were such as to give him an illustrious display of God's faithfulness to His promises. The period of Israel's journey and affliction in Egypt had been predicted (Ge 15:13), and it was during the last year of the term which had still to run that the Lord appeared in the burning bush.