I'll let scripture answer:
John 17:3 And this is life eternal, that they might know
thee [Father] the only true God, and Jesus Christ, whom thou hast sent.
1 Cor 8:6 But
to us there is but one God, the Father, of whom
are all things, and we in him; and one Lord Jesus Christ, by whom
are all things, and we by him.
John 20:17 Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and
to my God, and your God.