Theology: How much "heresy" is too much heresy?

Was reading in Matthew 24:14 recently: And this gospel of the kingdom will be preached in the whole world as a testimony to all nations, and then the end will come.

This verse is in one of the "end-times" passages. There are probably as many ideas of what the end times will look like as there are people speculating on the end times! If you read all of Matthew 24-25, the safest conclusion I think is: (1) the timing of the end is unknown and (2) it will catch most people by surprise.

But Matthew 24:14 appears to be the most clear cut statement about when it will happen.

And so how are we doing with the world evangelization plan?

The Joshua Project attempts to identify which ethnic groups have not been reached with the good news of Jesus.

One other question I've been pondering is the the role of "heretical" Christianity.

I found out while visiting the library of Uppsala University that has the oldest Bible manuscript in the Goth language is the so called "Silver Bible." In the 4th Century a bishop translated the Bible into Goth and evangelized the Goths of modern day Germany. None of the Bible copies from his time survive but the Silver Bible is a copy prepared in the 6th Century. That copy is in fragments containing much of the 4 Gospels but nothing else. Thus, the scholarly interest in the Silver Bible is for its value as the oldest example of the Gothic written language rather than as a contributor to textual criticism.

What is interesting theologically was that this bishop subscribed to an Arian flavor of Christianity!

My understanding was that the Arian Christology was a disputed and that argument that led to the Nicean formulation of the Trinity. The short version is that the historic view of Christ was that God the Father and God the Son were of the same substance while the Arian view (followers of Bishop Arius of Alexandria) was that God the Son was created by God the Father and thus of lesser substance.

Thus, the Goth people groups were reached with the Gospel by what was considered a heresy! These people who trusted in Jesus had no idea of the strict Christology that was stated in the early church councils! I suppose the bottom line is whether a person's life is transformed by their encounter with Jesus. Thus, their intellectual understanding of who Jesus could be muddled. My guess is that the thief on the Cross who trusted Jesus might not be able to answer all Christological questions but he indeed called on the name of Jesus from whom life and salvation pours forth!

So how much "heresy" is too much heresy?