The expression, his brightness was like the light,
highlights that God is perfect, pure, and holy. As light he acts according to his nature; therefore, whatever he does is just, good, and right. His coming as a bright light is to direct his judgment upon both his people and the Babylonians. As the sun penetrates the earth with its brilliant light so God, by his action, will reveal his power to his people. They will see the radiance of his glory through their experience of his judgment upon them and their witness of him delivering them from the Babylonians.
The rays that flashed from his hand refer to his power and emphasize his readiness to act on behalf of his people, to free them from the hardship imposed upon them by the Babylonians. It describes him displaying his sovereignty over the Babylonians by ending the affliction they had brought upon the Israelites.
The veiling of his power meant that the fullness of his wrath against the Babylonians would not be displayed in the same way against the Israelites. His veiling would show his mercy toward them.
4 His brightness was like the light; rays flashed from his hand; and there he veiled his power.