Ron Rhodes quotes Paul G. Weathers:
Since Christ came as man, and since one of the proper duties of man is to worship, pray to, and adore [God], it was perfectly proper for Jesus to call the Father "my God" and to address him in prayer. Positionally speaking as a man, as a Jew, and as our high priest ("made like his brothers in every way," Heb. 2:17), Jesus could address the Father as "God." However, Jesus did not relate to the Father in this way until he "emptied himsel" and became man, as it says in Phil. 2:6-8 Reasoning from the Scriptures with the Jehovah's Witnesses p. 152
The Bible does give an indication that Jesus addressing the Father as "my God" is due to the incarnation:
Psalm 22
1: My God, my God, why hast thou forsaken me? why art thou so far from helping me, and from the words of my roaring?
2: O my God, I cry in the daytime, but thou hearest not; and in the night season, and am not silent.
3: But thou art holy, O thou that inhabitest the praises of Israel.
4: Our fathers trusted in thee: they trusted, and thou didst deliver them.
5: They cried unto thee, and were delivered: they trusted in thee, and were not confounded.
6: But I am a worm, and no man; a reproach of men, and despised of the people.
7: All they that see me laugh me to scorn: they shoot out the lip, they shake the head saying,
8: He trusted on the LORD that he would deliver him: let him deliver him, seeing he delighted in him.
9: But thou art he that took me out of the womb: thou didst make me hope when I was upon my mother's breasts.
10: I was cast upon thee from the womb: thou art my God from my mother's belly.
Isaiah 49
1: Listen, O isles, unto me; and hearken, ye people, from far; The LORD hath called me from the womb; from the bowels of my mother hath he made mention of my name.
2: And he hath made my mouth like a sharp sword; in the shadow of his hand hath he hid me, and made me a polished shaft; in his quiver hath he hid me;
3: And said unto me, Thou art my servant, O Israel, in whom I will be glorified.
4: Then I said, I have laboured in vain, I have spent my strength for nought, and in vain: yet surely my judgment is with the LORD, and my work with my God.
5: And now, saith the LORD that formed me from the womb to be his servant, to bring Jacob again to him, Though Israel be not gathered, yet shall I be glorious in the eyes of the LORD, and my God shall be my strength. 6: And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth.
Unitarians admit that Jesus was a human on this earth, and thus they believe that Jesus as a man on this earth referred to the Father as "my God." What many of them fail to understand is that Trinitarians also believe that Jesus was a man while on this earth. Thus Jesus as a man referring to the Father as "my God" does not disprove the Trinity since the Trinty teaches that Jesus was (in addition to being God by nature) fully human.
The Watchtowers main response to this is to point out that even following the resurrection Jesus used the same expression:
"Repeatedly, even following Jesus' ascension to heaven, the Scriptures refer to the Father as "the God" of Jesus Christ. At John 20:17, following Jesus' resurrection, he himself spoke of the Father as "my God." Later, when in heaven, as recorded at Revelation 3:12, he again used the same expression." Reasoning fron the Scriptures p. 411 Watchtower Society
The Watchtower tries to argue that Jesus' refering to the Father as his "God" , could not be due to his being human (as Trinitarians claim), because according to the Watchower in the above instances (John 20:17; Revelation 3:12 etc.) Jesus was no longer a human. However, this reasoning assumes the WT doctrine that Jesus is no longer human since his resurrection. I hope to post some more inforamation on the continuing humanity of Jesus. If it shown that Jesus is a still a human following his resurrection, then the Watchtowers argument on this point evaporates.
Note: please try to keep posts in line with the specific subject of this thread. It is not my intention here for a lengthy Trinity battle, so please keep comments around the subject of this thead.