In contrast to creeds, which are basic statements of belief, confessions represent more detailed inquiry into the things of God. The creeds are the boundaries of the faith that separate orthodoxy from heresy, while the confessions color in the picture, tying theology to everyday life in all sorts of ways. Because creeds are bare-bones structures (the outlines of the sketch), it makes sense that the earliest statements of the church are creeds, while later statements of particular denominations are confessions. Creeds distinguish orthodoxy from heresy (or Christian faith from non-Christian faith). Confessions distinguish denominational distinctives (or one type of Christian faith from another type of Christian faith).

Christian confessions often define a particular group's belief on secondary issues such as infant baptism, the end times, predestination, the Lord's Supper, and the order of salvation. While the creeds aimed to preserve "the faith delivered for all time," confessions tried to apply the faith to the here and now.

Did the early church accept the councils as authoritative like we do? If not, how should that affect the way we view the creeds?

There are seven ecumenical councils that every branch of the church recognizes today, whether Orthodox, Catholic, or Protestant.

The first recorded instance of a church council is found in the New Testament. The Jerusalem Council is the name given to the meeting of church leaders of Antioch (with Paul and Barnabas) and of Jerusalem in which the large growth of Gentile converts in the early church was discussed (Acts 15:2-29).

Like the Jerusalem Council, church councils were called to address not only disagreement over a theological issue but also the practical ramifications of that issue. For instance, in the Council of Nicaea the question being asked was, "How can we worship one God (the Father) and also worship Jesus Christ?" Though this was a practical question about worship, it couldn't be disconnected from the more abstract theological issue of how Jesus Christ is related to his Father. The council affirmed that both Jesus and the Father are members of a single being, God.

So are the councils' decisions authoritative? It's instructive to notice that when Paul is asked whether Christians should eat food offered to idols (1 Cor. 8:1-13), he appeals not to the decision of the Jerusalem Council but instead to the revelation he'd received from Jesus Christ. This shows that Paul saw the Jerusalem Council as authoritative in some sense but not ultimately so. His appeal was to God's revelation as the arbiter of truth, not to a human decision at a council.

I believe that the creeds produced by the ecumenical councils are authoritative, but just not the final or only authority.

Is the "Great Tradition," as the collection of early creeds are often called, sufficient for Christian unity?

It is necessary but not sufficient. My understanding of "Christian unity" includes doctrine but also other things that bind us together, such as practice, prayer, and love. Basically, I don't think it's enough to define "Christian unity" as saying the Nicene Creed without crossing your fingers.

A unity held together only by orthodoxy (right doctrine) is weak and dangerous. Without orthopraxy (right practice) and orthopathos (right affection), orthodoxy encourages Christians to view faith as a head-trip.

A unity with multiple dimensions is seen in passages like John 13:35, Romans 10:3, Proverbs 19:2, and Ephesians 4:1-6.

Which heresy is most "live" today, even if in slightly repackaged form? How about one on the horizon?

Repackaged teachings from Pelagius and Socinus are the most "live" today. My summary of Pelagius's heresy is "God has already given us the tools we need." Pelagius developed an ascetic form of Christianity with an overly optimistic theology of human nature. My summary of Socinus's heresy is "the Trinity is irrelevant, and Jesus' death is only an example."

Pelagius correctly saw human nature as something good created by God. But he ignores humanity's fall (original sin), causing his theology to fall into error. First, Pelagius argued there's no such thing as original sin. In no way were we implicated in Adam's first sin. His sin doesn't make us guilty or corrupt. Instead, as Pelagius claims, "over the years [our own sin] gradually corrupts us, building an addiction and then holding us bound with what seems like the force of nature itself." Humans by nature have a clean slate—a state of neutrality—according to Pelagius, and it's only through voluntary sin through the exercise of an unhampered human free will that we are made wicked. Potentially, then, one could live a sinless life and merit heaven, for there's nothing intrinsically sinful about humans even after Adam and Eve's sin. Pelagius didn't consider us to be intrinsically damnable after the fall.

In short, Pelagius rejected the doctrines of original sin, substitutionary atonement (the idea that Christ's death in our place is a supernatural intervention to save us), and justification by faith (the idea that believing and trusting in Christ is the way to salvation).

Socinus held a unitarian view of God: only God the Father is truly and fully divine. Jesus, "the Son of God," received a unique divinely appointed office as the Logos, an office that deserves respect and even worship. However, for Jesus, that respect and worship were limited to his office and didn't extend to his person, which Socinus argued wasn't divine. Socinus contended that the ecumenically accepted doctrine of the Trinity couldn't be defended.

Given his understanding of the radical unity of God and, consequently, Jesus' merely human existence, Socinus's view of the atonement logically differed from commonly accepted views. He argued that since Jesus wasn't divine, his death couldn't have been intended to make satisfaction (as Anselm argued) or to pay a penalty on behalf of other humans (as the Calvinists argued). Instead, Socinus understood Christ's death to serve as a way for God to model true love and devotion and to demonstrate the way of salvation. Jesus, then, provided the unique and divinely anointed model for humans to imitate.