। ॥
In plain words
All must grant one cause of the world and of the 'I': a Lord whose power has no bounds. In this picture, what is seen and the one who sees, the canvas and the light as well: He, the One, became them all.
Word for word
By all, as cause of the world and of the 'I', some one Lord of boundless power is to be declared. In the picture here, what is seen and the one who sees, the canvas and the light too: he, the One, became these.