We believe that there is one God, eternally existent in three persons: Father, Son, and Holy Spirit.
This simple phrase is further amplified by the new EFCA statement of faith:
We believe in one God, Creator of all things, holy, infinitely perfect, and eternally existing in a loving unity of three equally divine Persons: the Father, the Son and the Holy Spirit. Having limitless knowledge and sovereign power, God has graciously purposed from eternity to redeem a people for Himself and to make all things new for His own glory.
There's a long tradition behind the notion of Jesus as fully God and fully human, dating at least back to the Nicea, as immortalized in the Nicene Creed:
And in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds; God of God, Light of Light, very God of very God; begotten, not made, being of one substance with the Father, by whom all things were made.
But with all due respect (but no more than due) to the church fathers, I'm not absolutely sure they got it right. There can be no doubt that Jesus represented himself as divine. I refer you to an excellent word study my Mom published over at the Pioneers' New Testament, on the subject of Jesus use of the "I AM" phraseology--a construct that made no sense at all in Greek unless it was hearking back to God's declaration to Moses at the burning bush (Exodus 3:14). There's no reasonable question that his hearers heard Jesus characterizing himself as divine, either, as they tried more than once to stone him for blasphemy when he said it (see John 10:30-33).
Nevertheless, Jesus also, and just as clearly, referred to himself and the Father in language that seems awfully much like he saw God the Father as truly and distinctly other than himself. Take for example Matt. 10:32-33, where Jesus speaks of acknowledging and/or denying people before his father, or Matt. 11:27 where he describes having authority delegated to him by his Father. Or look at Matt. 20:23, where Jesus tells James and John and their mom that the authority to decide who sits at his right and left hand, has been reserved by the father and is "not mine to grant." Perhaps most tellingly, Jesus' prayer to his Father in the garden that the cup of his suffering pass from him, does not sound like a unity of being. These passages all have their parallels in the other gospels; I'm not trying to be exhaustive here, but rather to point out the case that is to be made.
The question, then, is why we must make a big deal out of determining the appropriate Christology to think, in order to be judged a worthy disciple of Christ the King. It took between two hundred and three hundred years for the church to come to the point of carving out the distinction (Nicea was in the early 300s--a time when a lot else got loused up by the church as well). I submit that a healthier, and more biblical approach, would be to live with the tension of Jesus' divinity and his humanity--to recognize that when he referred to there being only one God, he was referring to his Father at the same time that he knew he, also, was begotten by the Father in a divine, non-human sense before creation, and then incarnated as the Word become flesh at a later point in history.
Bottom line, it doesn't take sorting out the finer details of this paradox, to get us down to the business of following him. We would do well to get our priorities in order.