Affirmations and summations of the faith have proved vitally important to believers, even from the earliest years of Christianity’s origins. Known as creeds, these synopses of Scripture and doctrine were used by believers as a way of sharing ecumenical testimony and orthodox beliefs.
Often, creeds come about as a defense against heterodoxy. Such also is the case with the formation of The Nicene Creed, originally produced as a response—from Emperor Constantine and Hosius (or Ossius), the Bishop of Cordoba—to the Arian heresy.
First, it should be clarified as to which of the Nicene creeds is being discussed. There are two to which learners often refer—The Nicene Creed formulated by the First Council of Nicaea in 325, or The Niceno-Constantinopolitan Creed written by the First Council of Constantinople of 381. The one most believers quote in liturgy or preaching is the later.
As stated, the original intent of the 325 Nicaean Creed was to respond against Arianism, which stated that the Son (Jesus) was created by the Father (that is, “God the Father”) and therefore not equal with the Father, meaning that Christ did not share in the Father’s “consubstantial nature” (that is, the character and essence of God which is His “God-ness” or deity). As for the addendum in 381, clarification was needed regarding the 325 creed’s use of the word “homoousios,” which means “of the same nature as,” or “from the substance of,” referring to the Son’s relationship to and with the Father. Also, anathemas towards heresies were removed in this later version.
While these comments are interesting history, what should be learned from these significant councils and their conclusions? It should be understood that some doctrines are difficult to comprehend, but they should be taught appropriately and effectively to continue the teaching of truth. This is especially true regarding the teaching of the trinity, understandings of which can often become hazy by attempts (even well-meaning ones) at analogizing, or by purposeful avoidance of the topic all together.
However, the avoidance of doctrine, especially of proper Christology and Trinitarianism, can have an impact. If we do not know the being-ness of the God we worship—His singular essence with three persons—we might be found to be worshipping a different God. We might even become misled as to which god or gods others claim to worship.
We know the disappointing feeling when, in our favorite TV show, a long-lost character returns to the scene—but is replaced by a different actor. That statement puts lightly what Leith says in a very articulate fashion: if Christ, a manufactured creature (the Arian claim) originating from God, died for the purpose of reconciling mankind to God, then perhaps God has not “fully come into human history through Jesus Christ.” That is to say, if for our reconciliation we had need a of being Who was fully God and fully human to unite ourselves to God, then perhaps that was not fully accomplished if Christ is only an actor for God, created and separate from the Father.
Yes, there are difficult things about doctrines. Not every person has the time or the desire to become a “boring” theologian and argue about metaphysical terms such as “ontological vs. economic relationships” within the Trinity. This is not required to maintain one’s self in sound doctrine either—God has blessed His people with teachers to share and synthesize such instruction.
This brings us full circle, back to the purpose of the creeds. Understanding and being humbled by the necessary time it takes to exposit Scripture, we may thank God for those who did much work for us to be able to succinctly summarize various teachings through the writing of creeds.
The Niceno-Constantinopolitan Creed (or, The Nicene Creed)
We believe in one God, the Father Almighty, Maker of heaven and earth, and of all things visible and invisible.
And in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds, Light of Light, very God of very God, begotten, not made, being of one substance with the Father; by whom all things were made; who for us men, and for our salvation, came down from heaven, and was incarnate by the Holy Ghost of the Virgin Mary, and was made man; he was crucified for us under Pontius Pilate, and suffered, and was buried, and the third day he rose again, according to the Scriptures, and ascended into heaven, and sitteth on the right hand of the Father; from thence he shall come again, with glory, to judge the quick and the dead; whose kingdom shall have no end.
And in the Holy Ghost, the Lord and Giver of life, who proceedeth from the Father, who with the Father and the Son together is worshiped and glorified, who spake by the prophets. In one holy catholic and apostolic Church; we acknowledge one baptism for the remission of sins; we look for the resurrection of the dead, and the life of the world to come. Amen.
 J. Pelikan and V. Hotchkiss, eds. (2003). Creeds and Confessions of Faith in the Christian Tradition
 A. Berardino, T. Oden, J. Elowsky, & J. Hoover, eds. (2014). Encyclopedia of Ancient Christianity, Volume Two; D. Patte, ed. (2010) The Cambridge Dictionary of Christianity
 J. Leith (1982) Creeds of the Churches: A Reader in Christian Doctrine from the Bible to the Present
 http://www.reasonablefaith.org/defenders-2-podcast/s5 – though others of us may find these discussions interesting, actually
 1 Timothy 4:14-16; http://www.desiringgod.org/messages/take-heed-to-yourself-and-to-your-teaching
 P. Schaff (1977). The Creeds of Christendom with a History and Critical Notes.