Despite the view of many Christians to the contrary, one need only refer to a host of Christian writers through the centuries to show that reasonable interpreters of the Bible have consistently upheld the doctrine of the unity of God throughout history.
A good example is Edward Elwall, prominent eighteenth-century Baptist merchant and writer of religious literature. In 1726 he wrote in his tract Dagon fallen upon his stumps, `Is it not as gross an Absurdity to say, the One God of Heaven and Earth, is Three or Four Persons, as to say, the One King of Great Britain and Ireland, is Three or Four Persons? Is not the former altogether as false as the latter?'
According to Elwall the Bible position is simple and straightforward. God is One (Exodus 20:3). Jesus Christ is our Lord and Master, the Messiah and reigning and soon coming King of the promised Fifth Monarchy of Daniel chapter two; our Savior, who was born of a virgin, lived a sinless life, worked great miracles and wonders by the permission and power of God, and was snatched up from the death of the cross and the grave to ascend to the right hand of God. But he is not God.
Elwall recognizes the authority of the ten commandments. These are the words revealed without intermediary to the multitude of humankind. These are above all the words of God Himself. To maintain that Jesus is God the Son is to break the first commandment, that is, Thou shalt have no other gods before me. Therefore Edward Elwall begins his tract with these words: 'Thou shalt have no other Gods but Me.
This Sacred Commandment was spoke by God himself, and not only so, but it was wrote by the Finger of God, therefore all those that Love him with all their Heart, and Soul, and Strength, ought to believe and obey this Law. Now let all Men that fear God, take particular Notice, that the very last word of this glorious Law, viz. (Me) is a certain Confutation of those who make the most high God to be a plurality of Persons.'
If Jesus Christ is not God, is not deity, then what is he? The Christian Scriptures are clear on the matter. `There is one God, and one mediator between God and men, the man Christ Jesus.' 1 Timothy 2:5. This text clearly contradicts the established Christian view that the mediator between God and man must be both man and deity. The logic of that thought notwithstanding, the Scripture states him to be clearly and unequivocally man and not God.
The position does not belittle Christ by saying that he is man and not God. It may be that he is a man so far above the men we know today that to human senses he would even appear to be like God. Nevertheless we must remember that human senses are not the criteria we are dealing with, but the Christian Scriptures. That Scripture states God to be one, and we have not the right to associate or confuse anyone, even one so great as Jesus Christ, with God Almighty. To do so is to fall into polytheism and, from an Islamic viewpoint, vastly to belittle and lower the concept of God.
What does the Bible mean then, when it says that Jesus is the son of God? In most modern languages it is rare to use the words father and son in other but literal meanings of biological descent. That is why readers of the Bible in translation may be honestly mistaken. The word `son' as applied to Christ and the word `father' as applied to God must be understood as metaphorical, that is, in a meaning other than the literally biological one.
Indeed, few people actually understand them literally. No one, insofar as I know, actually believes that God had sexual intercourse with Mary to produce Jesus. Such an idea is revolting to most minds and is certainly not held by any of the established Christian creeds. God, even according to Christian belief, is not the father of Christ or any other humans in any literal sense.
The word `son' is clearly used in the Bible to express the character of people, and not always their biological descent. The word is used in both ways in 1 Samuel 2:12. `Now the sons of Eli were sons of Belial; they knew not the Lord.' It cannot mean that these young men had two biological fathers. The genes of only one sperm can naturally combine with the ovum to produce a genetically new individual. The margin of my Bible explains that the expression `sons of Belial' means `wicked men', that is `sons of wickedness'. A `son of God' is just the opposite.
What are the non-biological usages of the word father in the Bible? In Genesis 4:20-21 `father of such as dwell in tents' and `father of all such as handle the harp', suggest a meaning of `inventor, first, prototype'. The words father and sons are used in Genesis 10:21 in the sense of ancestor and descendants. Joseph was no doubt younger than Pharaoh, but still he became Pharaoh's father or counselor in Genesis 45:8.
The word father is used by a subject in addressing a king in 1 Samuel 24:11. Elisha, while the subordinate of Elijah the prophet, addresses him as father in 2 Kings 2:12. Again in terms of a servant to master, or in this case a soldier to a general, the accompanying soldier addresses Naaman as father in 2 Kings 5:13. Five distinct groups of meaning appear: 1) a literal biological father, 2) an ancestor, 3) an inventor or prototype, 4) someone who gives counsel or information, and 5) someone to whom absolute obedience is due.
Considering that Jesus says that he came to do nothing but his Father's will, the last definition of father is probably the most appropriate as applied to his relationship with God. Jesus is called the Son of God because he perfectly carries out the will of God. It was Christian failure to understand this true meaning that made it necessary, for example, to use another metaphor in the Qur'an for Jesus: servant of God. Neither metaphor completely describes the uniqueness of Christ the Messiah in the Scriptural belief system. They are only two expressions among many.
All such expressions as father and son, master and servant, are merely metaphorical and cannot perfectly describe anyone's relationship to God, whose being and essence are completely outside the realm of human expression and language. To say that a person is a child of God or a servant of God is only to point out the relationship as a recipient of divine grace and the responsibility of obedience. God is not anyone's literal father or slave master. Those are human relations that merely approximate or give a direction in understanding. The Bible uses other terms as well, such as `husband', for God, and metaphorically `unfaithfulness' for sin. All such expressions are only useful to the extent that they inspire one to submit to God's will. They are not intended to give information about the nature of God, His essence, being or attributes.
It appears that the expression Son of God is also used, similarly to the expression Son of Man, to intimate that Jesus is the promised Messiah. That can be inferred from Daniel 3:24, if this text has a messianic implication. Let it be noted that Jesus himself did not like to use the term at all. He preferred other expressions of his Messiah ship, most especially the expression Son of Man.