The Book of Genesis is a rather difficult one for modern people to grasp. It tells us that God created the universe in seven days and that he created the first man Adam from the dirt of the earth. Some take this account to be literal, others figurative and still others as a silly fairy tale.
I cannot say that I take the Book of Genesis literally, especially the early chapters, but I nonetheless take it very seriously. But there has always been one verse that I have found difficult to rationalize. In Genesis 1:26 God says:
“Let us make man in our own image, in the likeness of ourselves and let them be masters of the fish of the sea, the birds of the heaven, the cattle, all the wild beasts and all the reptiles that crawl upon the earth.”
The problem I had with this verse were the the pronouns us and ourselves and the adjective our. Who exactly is the us in question? Of course with the creation of man, God is involved, but who are the other persons or entities eluded to in this passage? After all God could have said, “let me create man in my own image, in the likeness of myself.”
But He didn’t. I believe the Jewish explanation for this passage is that God is speaking to his angelic host. But this explanation seemed odd to me as why would God, an omnipotent entity, consult with his angelic host on the creation of man, and why would he include their image with his own, higher image, in this process?
Instead, whenever I had read this passage it evoked the image of lesser gods consulting with one another on the creation of man. This evocation led me to suppose that the Genesis 1:26 passage was probably an old vestigial mythological tale, from the time when the Hebrews or their forefathers worshiped multiple gods.
However, there is another explanation, nearly two millenia old, which I have just come across and which is in full accordance with Christian monotheism. Many anti-trinitarian heretics believe that the concept of the trinity was first introduced at the Council of Nicaea in AD 325 and as such is foreign to the earliest teachings of Christianity. In an attempt to refute this heretical belief, Thomas King wrote a well researched article which showed that the early Church Fathers were in fact trinitarians, centuries before the Council of Nicaea.
While reading this article I discovered that Church Fathers such as Saint Ignatius of Antioch, Saint Irenaeus of Lyons, Saint Hippolytus of Rome and Tertullian cited Genesis 1:26 as scriptural evidence in support of the trinity. For instance Tertullian explains the use of the plural us as “already there was attached to Him his Son, a second person, his own Word, and a third, the Spirit in the Word….one substance in three coherent persons. He was at once the Father, the Son, and the Spirit.”
So according to Tertullian, and the other Church Fathers, God is speaking to himself, as He is not a single person but three persons. In a sense this passage is foretelling the trinitarian nature of God, at a time when no one believed or understood this to be the case, hence the Jewish exegesis that the us in question was God and his angelic host.
It is also interesting to note that one of the Hebrew names of God, Elohim (אֱלֹהִים), is a plural noun. While there are numerous explanations for why Elohim is plural, it seems that the simplest answer is that it is another revelatory hint by God of His trinitarian nature.
I suspect that many others have been confused by the use of the plural in Genesis 1:26 (also known as the plural of Majesty). However, what must be remember is that God, while being one, is a trinity, composed of the Father, the Son (Jesus Christ) and the Holy Spirit, and that this trinitarian conception, while being first promulgated by the New Testament, extends into the period and domain of the Old Testament, regardless of the fact that the Jews of that period were unaware of this conception.
The trinitarian interpretation of Genesis 1:26 has been accepted as orthodoxy by most of the ecclesiastics of the Orthodox Church, and other denominations, but unfortunately for most people, myself included, we are not as versed in biblical exegesis as we should be, and as such passages such as Genesis 1:26 can be a source of confusion, maybe even doubt.
But when confused and in doubt, before coming up with harebrained interpretations, it is probably best to consult with the Church Fathers. They seem to know what they are talking about.
 Citation taken from the Jerusalem Bible. http://www.amazon.ca/The-Jerusalem-Bible-Readers-Edition/dp/0385499183
 Tertullian Against Praxeus chapter 12
 The concept of the trinity is a rationally difficult one, because how can 1 be 3 and vice versa? In other words 1 ≠ 3. Logically speaking this appears to be either a paradox or a contradiction. For this reason it is not surprising that many heretical Christian groups have rejected the trinity. The complexities of the pertinent philosophical and theological arguments (see the Maverick Philosopher’s posts on the subject to appreciate this complexity) make it difficult for ordinary orthodox (in the general sense of the word) Christians to rationally accept or reject the concept of the trinity. As such for them the trinity is a matter of faith underpinned by the revelation of God.