Kabbalah zu Jeschijahu 42:13

that is [the meaning of] yasis. But what is the meaning of 'hero'? What heroism is in this? Rather, there are twelve windows in the heavens, [filled with] warriors adverse to Him guarding the gates. [Then,] the sun wraps himself in the letters of the tefillin, and dresses himself in might, as it is written (Isaiah 42:13): "The Lord goes forth as a hero." Thus he goes out "eager like a hero running his course", opening up all the windows of the heavens and creating twelve paths - just as Moses did in the [Red] Sea. Surely, He "runs his course", and since at first He took on [His aspect of] might, the [colour of the rising] sun is red.