You can't have it both ways. Either Jesus is God of God incarnate of the Virgin Mary, or He is in no way God. There are not levels of divinity in God. Either Mary is the mother of God or she is not. The ancient heretic Nestorius was willing to attribute honorific titles to Mary and he was able to describe her as bearing some kind of imposition by God, so that she would be a conduit of the divine to the world. However, it seems that Nestorius thought of her merely as a pipeline, rather than as a mother. God's Son only came through her. He passed through her, perhaps like sun through a windowpane. Then who is the One born of Mary? Is He merely man? Is He man who only bears the divinity? How are the two natures in Christ related to each other? Are they merely connected? If she bears only the Sun of righteousness, what does that mean? Nestorius was keeping the two natures in Christ, the divine and the human, separated from each other. Nestorius was trying to keep the divinity of Christ from being contaminated by too close a connection with humanity.

Nestorius was attempting to protect the holiness of God. That's a laudable, even if an implausible project, because God is more than capable of protecting His holiness without our help. Our task is to keep His name holy here by saying after Him what He has already said about Himself in His divine Word. It is not keeping God's name holy to bestow on Mary some series of honorific titles without being clear about the person of her Son, who is God of God and incarnate of Mary. If His divinity is merely "connected with humanity," what is the connection like? Are the two natures merely glued together like some cheap plywood that comes apart under a little pressure? When Mary bore her Son, whom did she bear? Is God-with-us? Or something lesser? Look at His works. He comes to enlighten all persons. He has created all things and still sustains them. He sends the message of the gospel until the end of the age. Can One who does such things be a mere godling, an appearance of God in the world, but not God Himself?

If Jesus is merely the indwelling of God in man, not God incarnate, the He is reduced to a Mormon god. Merely the best of all possible men, someone in whom the divine spark dwells. A lesser god is no god at all.

If these questions are left to fester among us, we can never be sure of our salvation. Who less than God could work salvation for us? Who only appearing to be God could be the high Priest who offers Himself for the sins of the whole world? Who could rise from the dead and also ascend to be seated at the right hand of His Father to fill all things? Yet the Bible attributes all these things to the God-Man as the working of our salvation. Let us not become children of a lesser god.