9 Moreover, He goes on in His own words, and troubles those that understand the matter amiss, in order to recall the erring to a right apprehension of it. After He had said, “The Son cannot of Himself do anything, but what He sees the Father doing;” lest a carnal understanding of the matter should by chance creep in and turn the mind aside, and a man should imagine as it were two mechanics, one a master, the other a learner, attentively observing the master while making, say a chest, so that, as the master made the chest, the learner should make another chest according to the appearance which he looked upon while the master wrought; lest, I say, the carnal mind should frame to itself any such twofold notion in the case of the divine unity, going on, He says, “For what things soever the Father does, these same also the Son does in like manner.”
It is not, the Father does some, the Son others like them, but the same in like manner. For He says not, What things soever the Father does, the Son also does others the like; but says He, “What things soever the Father does, these same also the Son does in like manner.” What things the Father does, these also the Son does: the Father made the world, the Son made the world, the Holy Ghost made the world. If three Gods, then three worlds; if one God, the Father, the Son, and the Holy Ghost, then one world was made by the Father, through the Son, in the Holy Ghost. Consequently the Son does those things which also the Father does, and does not in a different manner; He both does these, and does them in like manner.
Source: Tractates on the Gospel of John (New Advent)