The following is a sanitised version of the ideas I shared at our home group on 2nd Feb 2011.
1. The Hermeneutical Key (Gen 3v8-9)
Jay gives a whole talk highlighting theological differences between Islam and Christianity starting with these verses. The key point in these verses is that God on the Earth directly interacting with humans, something which could never happen in Islam. Two of the theological differences Jay talks about are sin and heaven/paradise.
In Gen 3 we see Adam and Eve hiding from God that is their sin has put a barrier between them and God. If God had visited the garden before (it seems reasonable to me that he would have done) then Adam and Eve wouldn't have been hiding from him, coz there wouldn't have been any sin. In Islam though God and mankind are separated even before sin comes, it is not sin that creates that barrier so sin in Islam isn't anywhere near as serious.
If man and God can walk and talk at the start then at the other end of history in heaven it seems reasonable that they will be able to walk and talk again. Certainly we will be in God's presence and be able to worship him. In Islam that separation will continue, God will not be in paradise with those that make it there. (Jay's paper)
2. The story of Joseph.
The Koran only has two complete stories; one of these is the story of Joseph in Sura 12. The bible story goes into much more detail; however amongst the details that they both include there are two differences.
The first is the price Joseph is sold into slavery for. The bible says that Joseph brothers "... sold him for twenty shekels of silver ..." (Gen 37v28). Here a shekel is a weight and 20 shekels is about 8oz. There is historical evidence that this is the right ball park figure for the cost of a slave in that era. Now the Koran says: "Then they sold him for a paltry price, a handful of counted dirhams; for they set small store by him." (Sura 12:20) and is talking about coins - something you count, yet coins didn't exist until 1000 years after Joseph. Showing that the historical details contained in the bible are accurate, yet the Koran gets these wrong.
The other difference is to do with Joseph's dream, the eleven stars and the sun and moon all bow down to Joseph's star. According to the bible in Egypt Joseph's eleven brothers all bow down to him, but Jacob is not recorded as bowing down to him and Rachel is dead (Gen 35v19) before the dream occurs (Gen 37v9). Thus what do the sun and moon refer to? the dream doesn't appear to be fulfilled. In Sura 12v100 Joseph claims the dream is fulfilled: And he lifted his father and mother upon the throne; and the others fell down prostrate before him. 'See, father,' he said, 'this is the interpretation of my vision of long ago; my Lord has made it true." In fact the dream isn't fulfilled that much better as Jacob and Rebecca don't bow down to him.
Gen 1v1 "... God created ..." Here God is Elohim, which is the plural form - in fact it is a 3 or more plural. While 'created' is singular, this is grammatically incorrect in the Hebrew. This grammatically error could be God way of indicating that there is something unusual about him like he is not a unity but a trinity.
Gen 19v24 NIV: "Then the LORD rained down burning sulphur on Sodom and Gomorrah—from the LORD out of the heavens." Lord in this verse is YHWH the personal name of God that is often pronounced Yahweh or Jehovah. If we read back from this verse then we will see that the first Lord has been on the earth talking to Abraham for previous couple of chapters. While the 2nd Lord is in the heavens. So there are 2 YHWH's working together to bring about the destruction of Sodom and Gomorrah. Today the best known bible (memory) verse is Jn3:16 and probably the most important doctrine is the love of God. In the early church the most important doctrine was the incarnation and this verse was the best known bible verse.
In Exodus 33 there are two verses which would be contradictory with one another if God is only a unity. In v10 we have "The LORD would speak to Moses face to face, as a man speaks with his friend." that is Moses looking into God's face. While in v20 Moses is not allowed to look into God's face and is only allowed to look at his back. The trinity explains this seeming contradiction, in v10 Moses was speaking with the 2nd person of the trinity, while latter in the chapter it is the 1st person of the trinity that he is not allowed to look into the face of.
Relationships between human beings are fundamental to the way the world works. Why would a Unitarian God put relationships at the centre of his creation, but since there are relationships within the Godhead it would be quite understandable for a Trinitarian God to do this. Further in the bible God is Love, while in the Koran one of the names of God is 'loving'. Now love requires an object. For a Trinitarian God this is not a problem because there can be love for the Son from the Father and love for the Spirit from the Son and love for the Father from the spirit. While for a Unitarian God this is a problem because it makes him dependant/contingent upon his creation. This argument can be extended to show that love requires God to be a trinity not just a duality, but my understanding of that part of the argument is much more woolly.
Jay did 3 debates with a Canadian Muslim called Shabbiar Alley in the 1990's. In the first of these Shabbiar produce a list '101 clear contradictions in the bible'. In the next debate Jay produced a paper giving explanations for these so called contradictions. Two of these are as follows.
2Sam24v1: Again the anger of the LORD burned against Israel, and he incited David against them, saying, “Go and take a census of Israel and Judah.”
1Chron21v1: Satan rose up against Israel and incited David to take a census of Israel.
So who was it that wanted the census? The result of the census was bad for the people of Israel. Satan wanted this as he always delights in people suffering, while God wanted it as a punishment on his people. So they both wanted it.
2Sam21v19: In another battle with the Philistines at Gob, Elhanan son of Jaare-Oregim the Bethlehemite killed Goliath the Gittite, ...
Now this contradicts the well known the Sunday school story in which David kills Goliath. However, in the Hebrew this verse doesn't scan it seems like there is a couple of words missing. In 1 Chron 20v5 it reads "... killed Lahmi the brother of Goliath the Gittite ...". Which confirms that a couple of words have been lost, this could have happened as manuscripts were very fragile and if these words were at the edge they could have broken off.
(We didn't get onto this issue due to lack of time.)
Sura 4v157 "... and for their saying, 'We slew the Messiah, Jesus son of Mary, the Messenger of God' -- yet they did not slay him, neither crucified him, only a likeness of that was shown to them."The standard Muslim interpretation of this koranic verse is that the person on the cross looked like Jesus but was not Jesus. Allah played a big trick on everyone and changed the appearance of someone else to make them look like Jesus. When investigating a crime or other incident the police would want to speak to people who actually saw what happened. The gospel writers and other first century historians who also mention the crucifixion were writing a few years/decades after the event. The Koran comes 600 hundred years later and so is too late to give any credence with respect to first century events. Now Muslims might response to that by saying that Allah is a perfect witness and so we should accept his testimony over all other things (when the Queen spoke up in the Paul Bural trail it was found innocent straight away). But what does that say about Allah? It says he is a deceiver and 'the best of deceivers' at that. Would God really be a deceiver? And moreover there are 2 billion Christians in the world today who are still convinced of this deception.